The Proper Care & Feeding of your Marine Fuel System

75500MAX Go2marineThe Proper Care & Feeding of your Marine Fuel System

One of the primary needs of your vessel’s internal combustion engine(s) is clean fuel. On many boats, an effective fuel filtration system is often overlooked when the boat is manufactured. With today’s fuel injected gasoline powered boats, fuel quality must be almost pristine to avoid problems with these engines. Contaminated fuel can cause the myriad of electronic sensors on these engines to give all mannerisms of improper signals to the engine’s computers and also give improper diagnostic codes to the mechanic attempting to troubleshoot them. Diesel-powered boats usually have a fuel filter on board, but even those can be upgraded to ensure that contaminant free fuel is getting to the engine.

Purchase Fuel Filters at

The most common problems usually begin with the introduction of water into the fuel. Water is commonly found in fuel systems and can come from a variety of sources. Condensation, fuel handling and environmental conditions are the main causes of contamination. Humid marine environments will increase the presence of water. Water contaminated fuel can lead to very severe engine damage if it is not detected and treated.

Contaminated fuel contributes to damage caused by oxidation (rusted metal parts) and suspended particles of iron oxide, microbiological growth and sulfuric acid damage, normally seen in diesel fuel. Fuel provides lubrication to the fuel injection system. Water displaces the fuel’s lubricating qualities increasing the chances of premature wear and galling.

Most factory installed filters such as those found in carburetors, fuel pump canisters and engine mounted filters do not have the capability of removing water. For this reason, the addition of a quality fuel filter/water separation unit is absolutely necessary to prevent the causes of engine damage. On most small gasoline powered boats, this can easily be accomplished with the addition of an accessory spin-on style fuel filter/water separation unit. These inexpensive units are commonly available at most marine supply stores and boat dealership parts counters. Be sure to size the system for your engine’s horsepower and fuel flow needs. These filter assemblies are usually very easy to install near the fuel tank in your boat. Always include a couple of replacement filters to add to your boat’s spare parts locker. If you encounter a bad case of water contamination while underway, which is caused by the fuel sloshing around in the tank mixing with the water, you will have the ability to drive the boat home rather than row it if you carry extra filters. This is because the water in the fuel will not pass through the filter and will plug the filter media decreasing the flow of fuel. You will notice this as a marked reduction in engine rpm’s which usually gets worse. Remove the contaminated spin-on filter, put it in a bucket for proper disposal later, and install a fresh filter. When you get back to shore, check into the problem as soon as possible to avoid further damage. When installing a fuel filter/water separator on your boat, be sure to follow United States Coast Guard guidelines for materials used and mounting locations.

An important thing to always remember is DO NOT use automotive fuel system additives or fuel dryers. This is because most of these products contain alcohol which ATTRACTS water into the system, compounding your problems. Always use marine fuel additives.

Diesel fuel systems, though more complex, will benefit greatly with the addition of a properly selected fuel filter/water separation system. Any vessel making long distance or offshore passages will be best served using a duplex system. This system uses two or more filters with a manifold and valve that allows the engine to continue operating on one filter while the other filter is being serviced. Most of these units utilize a vacuum gauge to determine filter efficiency and forewarn you of impending blockage. Vessels not going offshore will be improved with the addition of a properly sized single fuel filter/water separator assembly, but a dual system, though more expensive, provides an excellent margin of safety and reliability.

Most diesel fuel filter/water separator assemblies are sold with 2 micron filters however, the secret to the most effective and efficient fuel filtration is STEP-DOWN filtration. RACOR Filters states in their catalog, “A 30 micron filter (or primary filter) is used to filter raw fuel (or poor quality fuel) before it can be further filtered by finer medias such as a 10 or 2 micron. A 10 micron filter (or secondary and even final) is used to filter fuel which is known to be of very good quality. A 2 micron filter (or final filter) is the finest filtration available and is the last filter used prior to engine ingestion.” In other words, the first filter in line from the fuel tank (primary) should have a larger micron rating than the filter (secondary) located further on down the line or on the engine. The secondary filters are commonly 10 micron rated. If you use a 2 micron primary filter, a larger micron rated secondary filter will be doing absolutely nothing while reducing the overall efficiency of your system. The primary filter should be either a 10 micron or 30 micron rated filter. Keep in mind that using the small micron rated filters will also require more frequent filter changes. Exceptionally high fuel-flow engines, such as Detroit Diesels, should use the largest micron rating as the smaller sizes will restrict fuel flow and will need to be changed more often than necessary. Remember, it is fuel flow, not fuel consumption that determines the correct size of the fuel filter/water separator unit you use. Many engines use a fuel bypass system that routes unused fuel back to the fuel tank after it passes through the filtering system. Additionally, many small diesels are equipped with equally small fuel lift pumps. Using a small micron rated filter increases the load on these small pumps which can lead to premature failure. A properly sized primary filter used in conjunction with the engine mounted secondary filter will provide all the filtration needed to guarantee good fuel quality.

Fuel filter/water separator assemblies are available in both spin-on and drop-in element styles. Gasoline spin-on replacement filters are available almost everywhere. For diesel applications, the drop-in replacement element is considerably less expensive and much easier to find than the spin-on styles if you cruise to remote areas. A good rule of thumb, especially if you have difficulty servicing engine mounted secondary filters, is to change the primary filter twice to every secondary filter change.

It is surprising, but you can routinely find rust, sand and other small particles in your fuel. Sometimes even larger items can be present. Oxidized organic semi-solid contaminants such as carbon, gums and varnishes are the most common causes of plugged fuel filter elements. Efficient fuel filtration devices must be capable of retaining solid particle contaminants while also providing sufficient capacities for the natural organic contaminants found in diesel fuel.

In areas known to have contaminated fuel problems, pre-filters are commonly used. While these aren’t really filters as we normally think of them, they are very effective at removing contaminants and extending filter life. These pre-filters are cleverly designed to trap contaminants and be drained as necessary at regular intervals. Commercial fishing and charter vessels have successfully used these for some time and now, many pleasure boaters are installing them.

Whether you have a gasoline or diesel-powered vessel, the proper care and feeding of your boat and its total fuel system will provide you with many happy and trouble-free hours of boating pleasure.

Get out and enjoy your boat. If you need any parts, please visit us at, or call us toll free at 1-800-998-9508, 7 a.m. – 4 p.m. P.S.T. Monday – Friday. Happy Boating!

Michael Weller

Engine, Propulsion and Steering Systems Specialist

Fire Extinguishers and your Boat

Fire extinguisherNothing causes as much concern for a boater than a fire aboard while underway. Here is what happens in a boat without an automatic engine room extinguisher. Most boat fires start in the confines of the engine room, killing engine and electrical power to the vessel. One or two 2BC extinguishers cannot put out the enclosed fire.  The fire then spreads quickly to the rest of the vessel through all the flammables that are readily available, such as the wood trim and foam cushions. Soon the very fiberglass the boat is built from is burning. Ultimately, leaving no alternative but to abandon the vessel. The vessel burns to the waterline.

The key to fighting a boat fire is done at the dock before you leave the marina.

Here are the USCG minimum requirements for fire extinguishers onboard pleasure craft

  • For boats under 26′ – At least one B-I type approved hand portable fire extinguisher.
  • For boats 26′ to 40′ – At least two B-I OR one B-II type approved hand portable fire extinguisher.
  • For boats 40′ to no more than 65′ – At least three B-I OR one B-I plus one B-II type approved hand portable fire extinguisher.

Keep in mind that these minimum requirements are exactly that; the absolute minimum. A B-I type extinguisher equals 2 pounds dry chemical. A B-II type extinguisher equals 10 pounds dry chemical. These portable fire extinguishers are also rated to the class of fire they will be able to put out.

  • Class A: Ordinary Combustibles Includes wood, paper, cushions, canvas, fiberglass, rubber, many plastics, and other materials that burn easily and account for many boat fires. These can be extinguished with water.
  • Class B: Flammable Liquids Includes gasoline, propane, diesel fuel, oils, grease, paints, tars, lacquers, and flammable gases.
  • Class C: Energized Electrical Equipment Includes wiring, fuel hoses, circuit breakers, machinery, and appliances.

You will likely be using an approved BC Class (although it may be ACB) extinguisher. Using a portable dry chemical extinguisher will allow you to fight a fire ONLY if it is in the first couple minutes of a burn and you can spray the extinguisher at the base of the fire; after that, you are using the extinguisher to fight the fire as you exit the vessel. A portable fire extinguisher should be kept handy between the galley and the exit and a second one near the engine room.

Now for the engine room. Because of it’s caustic, noxious agent, discharging a dry chemical extinguisher into a fire may cause damage or even destroy the items that you are trying to protect. There is a superior, modern extinguisher medium (agent) called FM-200. This unique product leaves no residue and is safe to discharged near any electrical or mechanical equipment. FM-200 is even safe enough for discharge in occupied spaces! FM-200 systems reach extinguishing levels in 10 seconds or less, stopping ordinary combustible, electrical, and flammable liquid fires before they cause significant damage.

For use in enclosed spaces like an engine room, there are two operation modes available for Sea-Fire FM200 systems; automatic and manual / automatic models. A Sea-Fire automatic extinguisher is activated by the attached temperature sensor valve. Discharge will occur when the sensor valve temperature rises to the system activation point as shown in the specification table and on the label attached to each unit. The manual / automatic offer the ability to lead a manual discharge cable to a position outside the enclosed compartment (often the helm station) so that the extinguisher may be operated remotely. If an automatic / manual extinguisher is not activated manually, it will work as a normal automatic model and discharge when the system activation point is reached.

Sea-Fire manufactures FM-200 FD Series manual and automatic fire extinguishers for areas as small as 175 cubic feet and up to 1500 cubic feet.  The Sea-Fire FG Series are made to fit small engine rooms an other closed areas, from 25 to 240 cubic feet. Sea-Fire also manufactures the FT Series which are supplied with long, flexible narrow tubing that can reach into hard to access areas; such as the backside of electrical panels for spaces from 25-150 cubic feet.

In summary, dry chemical fire extinguishers are fine for trying to put out a fire on the stove, heater or open area. Sea-Fire FM-200 extinguishers are useful in enclosed spaces, occupied spaces and hard to reach spaces.

Remove Salt from Your Boat, Engine and Marine Equipment

Looking for a way to remove salt from your boat and other marine equipment including boat cooling system, cleats, other metal and fiberglass parts?

Salt-Away salt removal washing concentrate uses a carefully selected blend of ingredients that will provide optimum cleaning for your boat and boat engine. Salt-Away washing concentrate provides salt removal from virtually any surface.

Salt-Away uses a water-based 100% – Non-Hazardous, Non-Toxic, and Biodegradable blend of ingredients that dissolves salt crystals from surfaces. Water alone cannot do this.

Salt-Away flushes salt from inboard/outboard engines.

Many boats have engines using a fresh water closed cooling system. Some boat owners do not realize that the raw water side of the engine, where salt water passes through the heat exchanger and out the exhaust manifold, can have major salt corrosion problems. Without proper maintenance, this corrosion leads to expensive repairs.

Salt-Away has many uses:

  • Engine flush – Can correct engine over-heating by breaking down layers of salt accumulation
  • Cleaning diving & fishing gear
  • Seaside home maintenance – A/C units, patio furniture etc.
  • Power & Sail boat salt removal – sails, sail covers, line, hardware etc.
  • Boat trailer and trailer brake wash

Salt-Away is economical to use with a dilution rate of 500 to 1 ratio.

The Salt-Away SA32M Combo Kit combines a one quart Salt-Away concentrate bottle and a 6 oz capacity, re-usable Mixing Unit. The Salt-Away Kit is recommended as the “Starter Kit” for the Salt-Away salt removal product line.

  • 6 oz Salt-Away concentrate holding capacity
  • Mixing Unit connects to
    • Garden hoses
    • Pressure Washer in lines

Salt-Away cleaning solution can be used with other Marine Engine Flushing systems and units to keep your inboard and outboard engine cooling system clean. When used with other Marine Cleaning Tools, Salt-Away removes salt build up and gets parts and surfaces ready to protect with wax or polish.

Go2marine has many more items to help boat owners care for, maintain and repair their boat. If you have questions about the care and upkeep of your boat, check our site or give us a call at (800) 998-9508

Improved GM Reduction Starters

Sierra has redesigned their line of permanent magnet marine GM Reductions Starters for 2020

The Sierra improvements to their GM Reductions Starters include:

  • Starters  now have all steel gear construction for a longer more reliable life on your boat.
  • Starters include a more efficient solenoid requiring less amperage. The previous solenoids could potentially over heat and fail from low marine battery voltage.
  • The upgraded starters are designed to reduce water intrusion with an improved housing that seals off the internal components.
  • Sierra has introduced a one way Duckbill Drain Valve in the event of moisture or water entering the starter housing.
  • Sierra is now painting the starter housing to reduce rust and corrosion found in the marine environment.

The updated GM Reduction Starters include three models that fill the needs of many power boat owners and include

If you needs to find a starter for another make or model marine engine, or other parts for your Mercruiser, Volvo Penta or OMC powered boat give Sierra Marine Engine and Drive Parts Sonar Finder Tool a try on our our site,

Give us call if you have questions about any of your boating or marine needs at (800) 998-9508

CDI Electronics for Outboard Engines

CDI Electronics

CDI Electronics is the worldwide leader in aftermarket electronic ignition replacement parts for outboard engines. All CDI Electronics replacement parts are 100% manufactured and tested in the USA and have been for over 30 years.

CDI Electronics

The CDI Electronics product line covers Switch Boxes, Ignition Coils, Stators, Triggers, Rectifier Regulators, Timer Bases, Shift Assist Modules and more. Plus, CDI continues to develop new products so if can’t find what you’re looking for on our site give us a call and we can get it for you.

CDI Electronics have direct replacement parts for Johnson Evinrude, Mercury Mariner, Chrysler Force, Yamaha, Suzuki, Tohatsu, Nissan and Honda outboard engines.

In many cases CDI replacement parts exceed the OEM part in quality and in all cases carry a longer warranty. CDI Electronics offers a 2-year warranty vs. OEM warranties of 1 year.

CDI Electronics offers a toll-free number for technical assistance and application guide.

CDI Electronics also offers a comprehensive trouble shooting guide for most outboard applications. You can see the guide here.

Remember, Go2marine is proud to sell CDI Electronics parts and has engine specialists standing by to assist you finding the correct parts for your boat and engine Monday to Friday 7am – 4pm Pacific time.

Barr Marine Manifold by EDM

Replacing your marine manifolds is inevitable if you own your boat long enough. Fortunately, there are aftermarket manifolds available at a substantial savings vs. the OEM manifolds.

That being said; not all aftermarket manifolds are created equal.

Barr Manifolds by EDM are the only aftermarket manifolds available made in the USA. Barr casts, machines and inspects all their products to the highest of standards right here in the states.

Ford marine engine manifold by Barr Marine

Barr by EDM offers replacement manifolds, risers and related exhaust parts for most current gas engine makes and models including Mercruiser, OMC, Volvo Penta and Crusader.

Barr Manifolds and Risers have thicker internal walls for a longer life vs. their aftermarket, imported competitors.

All Barr OEM replacement Manifolds and Risers come painted to match the OEM color and fit right in on your boat’s engine.

All Barr Manifolds and Risers come with the required gaskets and mounting hardware for standard applications. Some fresh water cooled applications may require extra gaskets or block off plates, but we have those available.

Barr Manifolds, Risers and Exhaust Connectors are designed to minimize back pressure, and in many cases, after replacing the OEM manifolds with Barr Manifolds and Risers, engine R.P.M.’S are increased resulting in better performance and increased fuel economy.

Barr Manifolds and related parts come with a 3-year limited warranty against manufactures defect.

You can start your manifold search here. For application assistance or general questions call the Engine Specialist at Go2Marine (800) 998-9508

Electronic Ignition for Your Boat’s Engine

Pertronix offers Electronic Ignition Conversion Kits for most engines with conventional contact type ignitions used in the Marine Industry.

Pertronix Electronic Ignition

Pertronix Electronic Ignition lets you get better performance from your boat’s marine engine.

Standard contact type ignitions (points and condenser) are unreliable since as the points wear, the ignition timing is reduced causing sluggish engine performance.

Installation of Pertronix Electronic Ignition kits is as simple as removing your old points, condenser and breaker mounting plate then installing the new Flame Thrower Module in its place. You’ll adjust the ignition timing one last time and will have a modern high performance, maintenance free ignition system.

With the addition of a Flame Thrower coil matched to the Electronic Ignition, the voltage will increase from 24,000 volts to 45,000 volts resulting in quicker starting, better overall performance and increased fuel economy.

See the Pertronix Ignitions and coil to find the one right for your boat. For technical help or engine application questions, call Go2marine @ 800-998-9508

Troubleshooting Power Trim and Tilt Motors and Pumps

tilt trim

Tilt and Trim Motor

Replacing Power Trim and Tilt Systems

When replacing your Power Tilt and Trim Motor, first identify what type of Power Tilt and Trim Motor and Pump you have in your boat. There are two basic types of power Trim and Tilt Systems being used in the recreational Boating industry regardless of weather you have an Outboard or an I/O  Sterndrive.

Some of the older Power Tilt and Trim Systems used an Electric Tilt Motor in combination with a mechanical lifting device. For example, Volvo Penta used a 12-Volt Power Tilt Motor turning a lifting screw on their older Stern Drives. On older OMC Stern Drives, an electric Motor turned a Worm Gear and incorporated a wet clutch pack to Tilt the drive unit as well as lock it into place. The Electric Hydraulic power Trim and Tilt System is more common. This type of system is used on Johnson and Evinrude Outboards, Mercruiser Stern Drives, Mercury Outboards and Volvo Penta Stern Drives. This system consists of two major components; the 12 volt electric Motor with a reservoir, and the Hydraulic Pump or Valve Body.

Trouble Shooting Your Power Trim and Tilt System

When experiencing problems with your power Trim and Tilt System, there are a few easy ways to diagnose just what the problem is. Power Trim Motors generally come in two styles. All use a 12 volt D/C reversing Motor. Some Motors have a two wire connection and some Motors have a three wire connection. All power Trim and Tilt Motors come with one blue wire and one green wire. The three wire power Trim and Tilt Motors have an additional Black wire as well. The Black wire works as a Ground on power Trim and Tilt Motors that don’t ground thru the case. When the blue wire is energized it raises the Motor or drive unit up. When the green wire is energized it lowers the drive unit down.

When having a problem first you need to determine whether your problem is with the power Trim and Tilt Motor or the Hydraulic Pump Valve Body assembly. If you attempt to raise the Motor or sterndrive to the up or down position and nothing happens, first check to make sure your Battery is charged and switched on if your boat is equipped with a Battery switch. If you hear a slight clicking noise you have power coming from the switch to the solenoid. The next step is to go directly to the Motor and test it there. First, disconnect the power Trim and Tilt Motor.

Using a jumper wire, apply 12 volts directly to the blue wire if your engine or drive unit is in the down position. It should raise up at this time. If it is in the up position, apply power to the green wire reversing the Motor and lowering the unit. If the Motor runs, you may have a problem with a solenoid or lack of voltage coming from the power Trim and Tilt switch to the solenoid.

If your power Trim Tilt Motor won’t run after this procedure it is time to replace it. Some replacement Power Trim and Tilt Motors will come with a new wiring harness and relay kit to convert your old three wire power Trim and Tilt Motor to a new more powerful two wire Motor.  (Tilt and Trim cross-reference)

Power Trim and Tilt Pump Problems

Tilt and Trim Pump

If your power Trim and Trim Motor is working fine but the engine or drive unit won’t stay Trimmed or bleeds down when in the up position, you most likely have a problem with the Hydraulic pump or Valve Body assembly. In that case it can be removed and rebuilt by a qualified repair facility. Replace the power Trim and Tilt hydraulic pump unit and fill the reservoir with the correct Power Tilt and Trim Fluid per your owner’s manual. Generally, Transmission fluid is not recommended. It can be hard on some seals due to the high amount of detergents. Most power Trim and Tilt units will purge the air from the system just by running the engine or sterndrive up and down two or three times with the vent plug loose.

Bottom line

If the motor works in one direction there is nothing wrong with the motor. The most common issue is a bad solenoid on a 3-wire motor or a bad relay on 2- wire motor. If the motor runs but won’t raise or lower the drive or outboard engine, check the fluid level first. If the level is full there is a problem with the pump. API Marine makes a direct replacement for many models (in some cases your only option is to have the old pump rebuilt).

Hope this helps you repair your tilt/trim system so you can get out and enjoy your boat. If you need any parts, visit us at, or call toll free 1-800-998-9508.

Article by: Michael Weller
Sales Manager

Engine, Propulsion and Steering Systems Specialist

Replacement and Installation of Marine Engine Mounts

Marine Engine Mounts have come a long way from the days when an engine was welded or bolted directly to the engine bed or stringer. When this was a common practice, the engines were huge, heavy, low rpm engines. These engines were so heavy and slow turning they absorbed whatever vibration that might have been generated. Today’s modern gasoline and diesel engines are much lighter in weight and operate at considerably higher rpm’s than older generation engines. This change is largely due to the never-ending race for more horsepower.

In order to develop more horsepower and efficiency, and also meet the new, more stringent EPA requirements, lighter weight, high rpm engines are becoming the industry standard. The lighter mass of these engines does not allow them to absorb the harmonic vibrations that are found in all engines at various operating speeds, so vibration isolating engine mounts are needed. Also, as the engine weights decrease and power (thrust) increases, the functions an engine mount must perform become much more complex.

How Engine Mounts Work

An engine vibrates in three different fields of motion; fore and aft (longitudinal), side to side (lateral) and up and down (vertical). All of these motions are controlled by the engine mount but not always to the same degree for each motion. Most engine mounts are designed to severely restrict longitudinal, fore and aft thrust and vibration yet allow some lateral and vertical motion to dissipate vibrations. A plain rubber doughnut mount will absorb vibration but in a marine engine, you also have the forward and reverse thrust (shear) generated by the propeller that must be controlled by the engine mount.

There are a wide variety of mount styles to choose from. Smaller diesels with one, two and three cylinders are more apt to use rubber doughnut style compression mounts which allow the engine to move the same in all directions. These mounts are built fairly stiff to control engine vibration and absorb propeller thrust. Generally, compression mounts are shorter and can fit in many applications. Find the correct engine mount with the engine mount cross-reference guide.

On larger, more powerful engines, propeller thrust is much greater so a shear type mount is used to control the thrust but it allows for greater lateral and vertical movement to isolate engine vibrations. This means the mount can be softer for better vibration isolation but is preloaded for superior control of longitudinal motion which also helps maintain better shaft and engine alignment.

If too stiff a mount is selected, the vibration control is minimized which means that engine vibration will be transmitted directly into the boat hull which will act much like a big loudspeaker with unpleasant results for the boat’s occupants. Proper sizing is very important to prevent this from happening.

One of the most common installation errors occurs when the engine mounts are installed on the engine bed improperly. It is imperative that the mounts are perpendicular to the engine’s crankshaft; so that when the mount stud goes through the engine bracket it is not pulled to the side, or fore and aft, preloading the mount. Also, the bottom adjusting nut on any mount should not be more than 3/8 of an inch off the base of the stud. Raising the engine too high greatly increases the engine mounts dynamic load and the mount will not function as designed. It is best to put a shim under the mount rather than raise the nut too high.

Mounts do age, fatigue and even fail, so periodic replacement is a good preventative maintenance measure. Some engine manufacturers recommend mount replacement every five to seven years. If you are replacing a broken mount, it is best to replace all the mounts due to fatigue caused when the intact mounts take on the additional load from the broken mount. If you choose not to do this be sure to replace the mount with the exact same mount. Using a different style or weight mount could induce failure of the old mounts. Too stiff a mount will break when used with softer mounts because it will not move as much as the softer and older mounts.

Mounts with cast aluminum bases are preferable because they offer better corrosion resistance. Steel components of the mount are usually zinc plated and passivated to resist corrosion. Some mounts offer a metal shield over the rubber damper to protect it from petroleum contaminants. Also, some mounts are mechanically captive which means the stud will not pull out of the mount in roll over or severe impact situations. If your vessel strikes a submerged object that damages the propeller or shaft, be sure to closely inspect your mounts for damage or breakage. This is sometimes difficult to determine so use a bright light and a mirror to check all the way around the mount for cracks, broken studs or a displaced rubber damper in the mount. It is not uncommon to find broken mounts on recently surveyed vessels so it pays to periodically check your mounts and replace them if they are fatigued or damaged.

You can enhance the life of your mounts by keeping them clean and free of corrosion and oil coatings. To ensure that you get the marine engine mounts best suited to your application, always follow the engine mount manufacturer’s guidelines.

How to Select a Balmar Charging System


 There are numerous reasons to upgrade your charging system. Here are some common complaints:

  • I can’t keep my battery charged!
  • My current alternator does not keep up with my electrical requirements/load.
  • I don’t want to run my engine just to charge the batteries.
  • I don’t want to run my generator to charge the batteries when my engine is already running.
  • I’ve added several batteries to my house bank, but I don’t think they are being charged effectively.
  • I operate predominantly at idle speed, but my battery bank doesn’t charge at idle.
  • I keep burning out alternators and/or batteries.
  • I have two engines, but my alternators don’t work together to charge the battery bank effectively.
  • My alternator charges my house bank, but I want to charge the engine start battery too without remembering to flip a battery switch.

Balmar Charging Systems can solve all these problems and more…

Selecting a charging system upgrade for your vessel can be a confusing task, as there are many inter-related variables to consider. The following guide steps you through a logical progression of questions and choices which must be made to select the best charging system for your needs. The selection process includes the following steps:

Step 1: Determine Your Vessel’s Electrical Load
Step 2: Identify Your Existing Battery Bank Technology and Capacity
Step 3: Select Your Optimum Alternator Output

Step 4: Identify the Alternator Mounting Style Present on Your Engine
Step 5: Determine your Belt and Pulley Requirements
Step 6: Select Additional Charging System Options

These 6 important steps are fully described below – Read on!

DC Load ChartStep 1: Determine Your Vessel’s Electrical Load
Skip this step if you are confident in your house bank’s ability to service your existing vessel loads

Accurate load calculations require precise measurement of your vessel’s equipment. Refer to equipment manuals for actual load ratings or consult with a qualified marine electrician to determine your actual needs. The chart at the right provides typical DC marine loads and an example of load calculations. Use this example to configure and calculate your vessel’s electrical load. Click here to upload Balmar’s interactive Load Calculator and save it for your personal use.  You can manipulate the Load Calculator in either Microsoft Excel or Google Docs.

(Device Load x Duty Cycle) x (# of Devices) = Total Load

House battery capacity is typically derived based on the ability to meet approximately 24 hours’ worth of typical demand, but could be longer if you don’t expect to be connected to shore power for extended periods. For example, if your vessel’s typical daily electrical load is 300 Ah, then your battery bank should be sized to provide 300Ah of power storage. Since your batteries will be damaged if you discharge them beyond a 50% State of Charge (SoC%), then 600Ah of rated storage is required.

Add batteries to your bank if you need them!

Step 2: Identify Your Existing Battery Bank Technology and Capacity

Battery bank capacity has a dramatic impact on the size and type of alternator required to keep the batteries healthy. Identify your battery bank technology and capacity, then calculate an acceptance requirement.

(A) Standard and Deep Cycle Flooded Batteries can accept a charge load up to 25% of their capacity.
(B) Gel Cell Batteries can accept a charge load up to 35% of their capacity.
(C) AGM Batteries can accept a charge load up to 40% of their capacity.
(D) Lithium Batteries can accept an almost unlimited charge load.

Contact your battery manufacturer to confirm their recommended charge loads and profile.

(Battery Storage Capacity) x (Battery Charge Acceptance Rate) = Maximum Alternator Output Current

For example, a bank of 3 AGM batteries, each with an individual capacity of 100Ah provide a total capacity of 300Ah. With an AGM acceptance rate of up to 40%, a 120A charging alternator could be utilized (300 Ah * 40% = 120 Ah). If you have a really large bank or a battery technology that calls for an alternator output that exceeds available alternator technology, then it will just take longer to charge your bank. Simply choose the highest alternator power which meets your budget and pulley constraints.

Mounting StylesStep 3: Select Your Alternator Output

Now that you know the battery bank technology and charging profile, you can choose an alternator output which will optimally charge your bank. The chart at the bottom of this page shows Balmar’s most popular range of small-case, high-power alternator choices for your vessel, along with an appropriate multi-stage regulator and related temperature sensing cables. (Balmar provides a discount when you buy the package).

For 70A – 120A requirements, choose a 6-Series Alternator Package.
For 165A – 200A requirements, choose an AT-Series Alternator Package.

Step 4: Identify the Alternator Mounting Style Present on Your Engine

It is critically important to determine how your existing alternator is mounted to match with the alternator you have chosen. Marine alternator mountings generally fall into one of four possibilities:

(A) 1″ Single Foot “Spindle” (Motorola-style – Westerbeke, Lehman, Hino, Pathfinder)
(B) 2″ Single Foot “Spindle” (Delco-style – Volvo, Deere, Perkins, Mercruiser, GM-based)
(C) 3.15″ Dual Foot “Saddle” (Hitachi-style – Yanmar, Westerbeke, Lehman, Perkins)
(D) 4″ Dual Foot “Saddle” (J180-style – John Deere, Cummins, Caterpillar)

Examples of these mounting styles are shown on the right. Review your existing alternator mounting to determine the appropriate mounting for your upgrade. Each Balmar alternator mounting style is identified by a unique part number.

Step 5: Determine Your Belt and Pulley Requirements

Engine drive belt style and width is also a critical factor when selecting a Balmar replacement charging system. Higher output alternators require more drive power to be taken off the engine. All belts have specific limitations regarding the amount of power take-off (“PTO”) loads they can support. Failure to specify an adequate belt/pulley system could result in premature belt wear, belt slippage and potential damage to the alternator and engine. Balmar alternators are shipped with pulleys which are appropriate for the alternator’s output.

6-Series Alternators from 70A-100A can ship with either a Standard 1/2″ Single Deep Vee, Dual Deep Vee or K6 Serpentine Pulley.*
6-Series Alternators from 120A-150A can ship with either a Standard 1/2″ Dual Deep Vee or K6 Serpentine Pulley.*
AT-Series Alternators can ship with either a Standard 1/2″ Dual Deep Vee or K6 Serpentine Pulley.*
Pulley Kit* Note: Balmar’s 1/2″ Deep Vee Pulleys (Single or Dual) can accept a 3/8″ and 7/16″ belt.

Identify the pulley style and size present on your engine and water pump before upgrading the charging system. If the alternator output you have chosen exceeds the capability of your existing belt/pulley system, you can upgrade the pulley system using one of Balmar’s patented Altmount Pulley Conversion Kits. Click here to find the applicable AltMount Conversion Kit for your engine and alternator choice. Here are some additional rules-of-thumb to guide your choices:

  • Balmar 6-Series Alternators from 70A-100A can perform with a 1/2″ Single Vee pulley. If you need to charge above 100A, then you will need a Dual Vee or K6 Serpentine pulley system to be present on your engine to avoid a pulley upgrade. If a Dual Vee or Serpentine is not present, then an AltMount Conversion Kit is required.
  • Many boaters choose to limit their charging system upgrade to a 100A 6-Series Alternator Package to avoid the additional purchase of a pulley conversion.
  • Unless you own a recently produced engine which already contains a Dual Vee or Serpentine pulley system, the superior power afforded by the AT-Series Alternator Package will in most cases require an AltMount Conversion Kit upgrade.
  • Choose wisely! Need more help? – call Go2marine Technical Support to review your existing configuration and needs.

With the completion of these 5 steps, you have reviewed all the critical variables required to choose the correct charging system upgrade for your vessel. The chart below identifies common small case configurations of 6-Series and AT-Series charging systems. Use our interactive Charging System Configurator to determine your exact needs.

Small Case Alternator Kit Selection Chart – Common Configurations

Balmar Product Family Output Power Take Off Mounting Alternator Part Number Balmar External Regulator Temp Sensors Alternator Kit Number AltMount
Pulley Kit
6-Series(2) 70 A 2.8 HP 1-2″ Single Foot (Spindle) 621-70-SV ARS-5-H(1) MC-TS-A & MC-TS-B 621-VUP-70-SV No
621-70-DV 621-VUP-70-DV
621-70-K6 621-VUP-70-K6
3.15″ Dual Foot (Saddle) 60-70-SV 60-YP-70-SV
60-70-DV 60-YP-70-DV
60-70-K6 60-YP-70-K6
100 A 4.0 HP 1-2″ Single Foot (Spindle) 621-100-SV 621-VUP-100-SV
621-100-DV 621-VUP-100-DV
621-100-K6 621-VUP-100-K6
3.15″ Dual Foot (Saddle) 60-100-SV 60-YP-100-SV
60-100-DV 60-YP-100-DV
60-100-K6 60-YP-100-K6
120 A 4.8 HP 1-2″ Single Foot (Spindle) 621-120-DV 621-VUP-120-DV Yes

If a Dual Vee or
Serpentine Pulley
is Not Already

See the

621-120-K6 621-VUP-120-K6
621-120-J10 621-VUP-120-J10
3.15″ Dual Foot (Saddle) 60-120-DV 60-YP-120-DV
60-120-K6 60-YP-120-K6
60-120-J10 60-YP-120-J10
70A, 24V 5.6 HP 1-2″ Single Foot (Spindle) 621-24-70-DV MC-624-H 621-VUP-24-70-DV
621-24-70-K6 621-VUP-24-70-K6
621-24-70-J10 621-VUP-24-70-J10
3.15″ Dual Foot (Saddle) 60-24-70-DV 60-YP-24-70-DV
60-24-70-K6 60-YP-24-70-K6
60-24-70-J10 60-YP-24-70-J10
AT-Series 165 A 5.2 HP 1-2″ Single Foot (Spindle) AT-SF-165-DV MC-614-H AT-SF-165-DV-KIT
AT-SF-165-K6 AT-SF-165-K6-KIT
AT-SF-165-J10 AT-SF-165-J10-KIT
3.15″ Dual Foot (Saddle) AT-DF-165-DV AT-DF-165-DV-KIT
AT-DF-165-K6 AT-DF-165-K6-KIT
AT-DF-165-J10 AT-DF-165-J10-KIT
200 A 6.0 HP 1-2″ Single Foot (Spindle) AT-SF-200-DV AT-SF-200-DV-KIT
AT-SF-200-K6 AT-SF-200-K6-KIT
AT-SF-200-J10 AT-SF-200-J10-KIT
3.15″ Dual Foot (Saddle) AT-DF-200-DV AT-DF-200-DV-KIT
AT-DF-200-K6 AT-DF-200-K6-KIT
AT-DF-200-J10 AT-DF-200-J10-KIT

UBB (Rotate)(1) An MC-614 Regulator can be substituted for the ARS-5 when support for a second alternator or twin engines is required. Smartgauge
(2) 6-Series Alternators are “Smart-Ready” and can be installed with or without a Balmar Multi-Stage Regulator.

Step 6: Select Additional Charging System Options

Now that you have selected an appropriate Balmar Alternator Kit, complete your purchase by adding a SmartgaugeTM Battery Monitor and a Belt Buddy Tensioning Kit!

1 2