Yamaha Primer Bulbs

Yamaha Primer Bulbs Resources and Information

The Yamaha Primer Bulb is used to fill the carburetor or injectors with fuel when the engine is started cold. Inside the Yamaha Primer bulb are two valves that open and close. Generally, it is not necessary to operate the fuel primer bulb before starting your Yamaha outboard engine. You may need to fix or replace your primer bulb if: It is not creating proper suction.

In addition to Yamaha primer bulbs, we’re proud to offer a complete selection of Yamaha outboard parts. 

Need help servicing your Yamaha outboard engine? We provide to following resources to help service your Yamaha outboard engine: 

• Yamaha Outboard Specs & Capacities Chart
• Yamaha Outboard Engine Schematics

Yamaha Primer Bulbs FAQs

What are common Yamaha outboard engine fuel system issues?

One of the most common ways your Yamaha outboard motor will break down is a fuel system failure. Whether you’re experiencing an intermittent bog down, poor performance, or complete engine failure, your fuel system is a common culprit.

• Ethanol gasoline: Only use premium low-ethanol gasoline for your Yamaha outboard motor. The reason is that ethanol attracts water, causing fuel to dilute through “phase separation.” Additionally, ethanol gasoline can also gunk up fuel lines and fuel system components due to additives used. To help prevent these issues, regularly use a high-quality fuel stabilizer.
• Fuel lines: Check your fuel lines. If you discover any breaks or leaks, you should stop using the engine and make any necessary replacements. Also, take a look at any fuel hoses with an interior liner.
• Fuel filters: The Yamaha fuel filter is designed to catch any debris and contaminants that have entered your fuel system. Regularly replace your fuel filters to keep fuel running freely.
• Fuel pump: A malfunctioning Yamaha fuel pump can significantly reduce engine performance and, over time, severely damage other components. If your fuel pump is not working correctly, replace it and any hoses that may have been affected.

How do I perform maintenance on 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.

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 the Yamaha 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 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 fuel system you need to check in our Yamaha and Mercury troubleshooting guides

How do you prevent Yamaha outboard motor fuel pump problems?

First and foremost, be sure that you’re performing the required engine maintenance at the recommended intervals. Our guides to engine maintenance for Yamaha outboards provide a basic checklist for this process, including all the parts that each manufacturer recommends you check for cracks, leaks, or other signs of damage and wear. 

Generally, fuel pumps themselves should be replaced as needed, but Yamaha specifically recommends that outboard fuel pumps should be replaced every 3 years. 

With regular maintenance, the proper Yamaha outboard service kit and the right set of tools, most outboard issues are fully preventable. Still, there are a few specific ways to keep your outboard motor’s fuel system in top shape.

Another option for supporting the longevity of your Yamaha outboard motor is Yamalube fuel stabilizers. Yamalube fuel stabilizers will keep fuel from going bad, remove carbon deposits, and protect the system as a whole during storage months. 

In addition, Yamalube fuel additives are necessary because ethanol gasoline is less than ideal for marine environments. Normal boating activity allows for more opportunity for the fuel to be exposed to water droplets, which bind to ethanol and forms a sludge-like material that is heavier than the remaining gasoline. It then sinks to the bottom of the fuel tank. When your Yamaha outboard fuel system picks this up, it can lead to clogs throughout. Preventing this with fuel stabilizers can help keep your engine healthy for far longer.

How do I choose the right marine fuel for my Yamaha outboard engine?

Using the right marine fuel for your Yamaha outboard engine is essential for reliable and optimal performance on the water.

Because different makes and models of boat engines require different fuels, using the wrong boat fuel can cause significant damage to internal outboard engine components as well as your boat’s fuel system.

For many boat owners, it’s common to feel a bit unsure as to which type of marine fuel is right for their engine(s). Choosing between different ethanol levels, mixing oil with fuel, and even using diesel can be downright confusing.

The following are the most common types of marine fuels for your boat:

• Ethanol-Free Gasoline
• E10 Fuel
• E15 Fuel
• Oil and Gas Mixtures
• Diesel Fuel
• Marine Gas Oil (MGO) and Marine Diesel Oil (MDO)

What is marine fuel?

Marine Gasoil is composed of blends of distillates. Distillates are the evaporated components of crude oil during the distilling process that are condensed from gas state to liquid state. Marine Gas may be compared to diesel, just that the density and storage requirements are different.

Ethanol-free gasoline is produced in a few different octane levels. REC-90 is marketed for boaters and for use in other small engines. It’s an ethanol-free, 90-octane unleaded gasoline blend designed for use in marine and small engines that ethanol found in other gasoline blends can damage.