Yamaha Outboard Fuel & Oil System Components

Yamaha Marine Engine Fuel and Oil System Components Resources and Information

PartsVu.com is happy to offer a wide selection of certified Yamaha outboard fuel and oil system components to match the exact specifications of your Yamaha outboard motor. If you have questions about performing maintenance on your outboard, chances are you’ll find the answers in our blog. 

Looking for more components and products to service your Yamaha outboard engine? Feel free to browse our Yamaha marine fuel pumps, or shop our complete selection of Yamaha outboard parts. 

We also regularly release new helpful resources like: 

• Yamaha Outboard Specs & Capacities Chart
• Yamaha Outboard Engine Schematics
• Yamaha Outboard Maintenance Parts Charts

Yamaha Outboard Fuel & Oil System Components FAQs

How do I service my Yamaha outboard fuel system?

Yamaha fuel system maintenance is a critical aspect of 100-hour service. Depending on your application and style of boat, you likely have a fuel-water separating filter aboard your vessel. If you have not seen one, simply follow the routing of your fuel hose from the engine rigging tube backward through the boat. These vary in shape and manufacturer, so be sure to order the identical replacement filter. Use a filter wrench to loosen the existing filter element and use caution when removing it as it will be filled with gasoline.

A clear plastic or glass container is helpful to dump the filter into and to examine the contents. A small amount of debris is common, as is a small amount of water after the fuel has had a moment to settle. Larger amounts of water would warrant further investigation. If your filter’s mounting location allows it, pre-fill the replacement filter with some gasoline to make re-priming the fuel system easier later. It is also advisable to use a small amount of grease to lubricate the o-ring prior to installation. Spin on and hand tighten only about a half turn to snug.

Continue your Yamaha fuel system maintenance by moving back to the engine and locate the filter element in the clear plastic bowl on the front of your block. Depending on your engine model, this filter cup may be removed by using a special cup wrench – or standard tools and a little caution. If applicable, unplug the water-in-fuel sensor and spin the cup off the housing. Again, drain into your clear container and examine the fuel. If your main water separator was free from water, this filter should be as well. Inspect the o-ring on the top of the filter cup and lightly grease for ease of installation or replace if needed. Replace the filter element with a fresh one and reinstall the cup. Use the cup wrench to tighten. Locate your engine’s primer bulb and use the primer to pump up the fuel system. You should observe gasoline entering and filling the filter cup. Check for leaks and prime until the bulb becomes firm. As a tip, primer bulbs work best when the arrow points up, so use any extra hose in the line to help you tilt the bulb vertical.

If you are not running Yamalube Ring Free on a constant basis, the 100-hour service interval is a great time for a “shock treatment.” Ring Free is a fuel system conditioner that also helps to remove carbon deposits. A standard dose is 1 oz per 10 gallons, but if you are not running the product all the time, you can double that ratio for more cleaning power. Simply pour the Ring Free into the fuel tank fill and go run the boat – no additional work is needed. It is advisable to inspect your fuel tank fill’s o-ring for damage when you add Ring Free as a damaged o-ring can allow water from rain or boat washing into your fuel system.

If you will be storing your boat for the season after service is performed, and liberal application of Yamaha’s STOR-RITE Fogging Oil and the addition of Yamalube Fuel Stabilizer & Conditioner Plus is highly recommended.

How do I change my 4-stroke Yamaha outboard engine oil? 

Prior to removing the old oil, check the dipstick level by lowering the engine to the running position and removing the cowling. Note if the cowling latches feel stiff or sticky. Latches are often overlooked during maintenance and are prone to salt accumulation for boaters who primarily boat in saltwater. If you discover salt accumulation of the latches, this residue should be removed – a salt remover may be required.

Yamaha color codes oil as yellow, so locate the dipstick and fill plug by looking for their bright yellow color. If the engine oil is high on the dipstick, it is possible that the oil was overfilled during the last service, or that the engine is “making” oil due to fuel contamination of the oil from improper ring seating or another serviceable condition. You should also note the smell and color of the oil. Dirty oil will appear dark brown to black in color. Milky brown oil indicates water contamination, whereas a notable gasoline smell indicates that your engine may not be reaching proper operating temperature, or that your rings could be allowing excessive blow-by due to carbon fouling or improper break-in.

Spent engine oil can be removed from the engine by extraction or via the oil pan drain screw plug. The extraction method requires the use of a vacuum extractor which is inserted down the dipstick tube and uses suction to pull the spend oil from the pan. This method tends to be very clean and is probably the most widely used among marine technicians. Alternatively, the drain screw itself can be removed. On inline Yamaha four stroke models (Yamaha F15 to Yamaha F150), the Seawell drain kit can be used to minimize the mess. On larger V6 models, to access the drain screw, remove the plastic chaps that cover the midsection of the engine. Be sure to have plenty of drain pan capacity as some of these engines can hold up to seven quarts of oil. We also recommend a petroleum sorbent pad to catch and errant drips and keep your driveway or lawn clean.

What are the symptoms of a bad fuel pump on my Yamaha outboard motor?

When you try to start your engine, you should be able to hear the sound of your Yamaha outboard engine fuel pump engaging. If that familiar sound can’t be heard, there’s a chance it could be due to issues with the battery. Check the battery first, and depending on other symptoms you may be experiencing, it could be a good idea to troubleshoot other systems with one of our handy guides. Still, if you’re missing that motorized sound, that’s a strong sign that the fuel pump may be having issues.

Another common symptom of a bad Yamaha fuel pump is sputtering or misfiring. If you’re experiencing a bumpy ride (or possibly losing speed altogether), it could also be a sign of a clogged fuel filter that won’t allow a consistent flow. You’ll want to check the entire Yamaha fuel system to ensure that any clogs and blockages in the system are addressed. We outline what parts of the Yamaha fuel system you need to check in our Yamaha troubleshooting guide.

Rapid fuel use is usually a sign that the condition of the fuel pump has deteriorated significantly. It’s a good idea to have an idea of how long a tank of gas will last you. If you notice that your tank is emptying faster than usual, it’s time to check out your fuel system before more problems take hold.

How do I perform a Yamaha fuel pump test? 

How do you test a Yamaha fuel pump on an Yamaha outboard motor? Fortunately, there are simple ways to test your fuel pump. This process assumes that you have already checked the rest of the Yamaha fuel system for cracks, leaks, and general signs of wear to ensure continuity between the Yamaha fuel tank and pump. You can check this by pumping the primer bulb until it feels hard. Fuel should travel easily from the tank all the way to the pump. Your outboard fuel filter, located just before the fuel pump, should be full. 

1. With the engine off and the cowl cover removed, remove the spark plug wire boot and remove the plug
2. Attach the compression gauge to the spark plug hole. Then, twist the throttle position wide open and either pull the rope start or turn the starter over several times.
3. The proper PSI will vary based on the engine, but in general, a low PSI (under 30) means that there is a compression issue that is preventing the fuel pump from working. If you have adequate pressure, this is indicative of a bad fuel pump.

The two parts of the fuel pump that are most commonly the source of problems are the diaphragm and the one-way valves. To test them, it will be easiest to remove the pump from the engine.