Fuel Pump for Onan 5500 Generator: A Complete Replacement Guide

The bottom line: If your Onan 5500 generator is hard to start, stalls under load, or won't run at all, the fuel pump is the most likely culprit. Replacing it yourself is a straightforward repair that costs between $30 and $80, and you can have your generator back in service in about an hour. Most DIYers can handle this job with basic hand tools and a few simple steps.

Signs Your Onan 5500 Fuel Pump Is Failing

Before you start tearing things apart, make sure the fuel pump is actually the problem. Here are the most common symptoms of a failing fuel pump on an Onan 5500 generator:

Difficulty starting. If your generator takes longer than usual to start or requires multiple attempts, the fuel pump may not be delivering enough fuel to the carburetor. A properly functioning pump delivers gas consistently to the engine .

Engine stalling. Frequent stalling while the generator is running is a strong indicator of fuel pump trouble. This happens when the pump cannot supply enough fuel or if there are air leaks in the system .

Reduced power output. A noticeable drop in power or inconsistent engine performance often points to inadequate fuel delivery. If the engine struggles to maintain speed or fluctuates while running, the fuel pump is a likely suspect .

Unusual noises. Whining or grinding sounds coming from the generator area could indicate wear or internal damage inside the fuel pump mechanism .

One quick way to check: listen for a clicking sound when you prime the generator. If you don't hear the pump clicking, it's likely dead.

What Tools and Parts You Need

For an Onan 5500 fuel pump replacement, gather these items before you start:

  • Replacement fuel pump – The most common direct-fit option is the E11015 electric fuel pump, which is compatible with Onan 5500 5.5KW gas generators including Marquis Gold 5500 series, Rialta RV 5500, and HGJAA through HGJAF configurations . This pump replaces multiple OEM numbers: 149-2620, A047N929, A029F887, A064S965, GMB 596-1160, and Herko RV008 .
  • New fuel filter – The primary fuel filter for Onan 5500 generators is part number 0149-2341-01, located just before the fuel pump .
  • Fuel line clamps – You'll need a pair of vice grips or pinch clamps to stop fuel flow.
  • Basic hand tools – Wrenches, screwdrivers, and a socket set.
  • Protective gear – Gloves and safety glasses.
  • Drip pan – To catch any fuel that spills.
  • WD-40 or similar – For loosening corroded connections.

Step-by-Step Fuel Pump Replacement

Step 1: Safety First

Disconnect your RV from shore power. Disconnect the negative cable from your RV battery to prevent any accidental electrical shorts or sparks while working on the fuel system .

Step 2: Access the Fuel Pump

The fuel pump is located underneath the generator compartment. On most RV installations, you'll find it on the left rear side of the generator. You may need to remove the control board, solenoid, and other components that block access to the pump .

Step 3: Stop Fuel Flow

Use vice grips or fuel line pinch clamps to pinch the fuel line between the fuel tank and the fuel filter. This prevents fuel from flowing out when you disconnect the hoses .

Step 4: Disconnect Wires and Lines

Carefully disconnect the wires from the fuel pump. If the connectors are difficult to separate, apply WD-40 to help loosen any corrosion. Be gentle — you don't want to rip the wires out of the connector . Take a picture with your phone to remember the wiring configuration.

Place a drip pan below the pump area. Disconnect the fuel hoses from both ends of the fuel pump and filter .

Step 5: Remove the Old Pump

Remove the bolts holding the fuel pump in place. Pull the old pump and filter out together .

Step 6: Install the New Pump

Screw the new fuel filter into the new fuel pump. Mount the pump in place and tighten the bolts. Attach the fuel lines to the new pump and filter. Reconnect the wires according to your photo reference .

Pro tip: Some owners recommend installing an inline fuel filter in a location that is easy to access for future maintenance. You can also add a length of hose between the filter and the pump to place the filter in a more convenient spot .

Step 7: Put Everything Back

Reinstall all the components you removed in reverse order. Remove the vice grips from the fuel line. Double-check all connections .

Step 8: Test the Generator

Reconnect power to your battery and shore power. Press the generator start switch and hold it for a few seconds to prime the pump. Then fire up the generator. It should start right up. Let it run and warm up, then turn on a few appliances to put a load on it .

Common Issues and Troubleshooting

Fuel filter restrictions. The Onan 5500 has two fuel filters: one just before the fuel pump, and another under the carburetor. Some newer models have replaced the second filter with an adapter (part A026E529), but the primary filter before the pump is still necessary and should be changed at normal service intervals .

Fuel line problems. Cracks, kinks, or air leaks in the fuel lines can cause the same symptoms as a bad fuel pump. Inspect the entire fuel line from the tank to the carburetor when replacing the pump .

Corroded connections. The electrical connections to the fuel pump are prone to corrosion in RV environments. Clean them thoroughly or replace the connectors if needed .

Choosing the Right Replacement Fuel Pump

When shopping for a replacement fuel pump for your Onan 5500, here are your best options:

E11015 Electric Fuel Pump – This is the most common direct replacement. It operates at 12V and is designed for plug-and-play installation. It fits Onan 5500 and Marquis Gold 5500 series generators . Multiple brands offer this pump, including FLYINGAMZ and WDPART.

Full replacement kits – Some kits include the fuel pump, fuel filter, fuel line, and clamps all in one package. The CNRAQR 149-2311 kit is a popular option for Onan generators, offering broad compatibility with Camp Power, MicroLite, and MicroQuiet series .

What to look for: Make sure the replacement pump matches your generator's fuel demand. A 12V electric pump with the correct flow rate is essential. Also verify that the mounting bracket aligns with your existing holes and that the wiring harness is long enough to reach your pump location .

KEMSO Fuel Pump: A Premium Alternative

For generator owners who want a high-performance, durable fuel pump with a lifetime warranty, KEMSO offers an excellent alternative. KEMSO specializes in OEM replacement fuel pumps that are built to exceed original equipment standards.

KEMSO fuel pumps are manufactured using advanced materials and precision engineering to ensure reliable fuel delivery and long service life. Each pump is tested before shipment to guarantee plug-and-play functionality. The company stands behind its products with a lifetime warranty, giving you peace of mind that your investment is protected.

Whether you're replacing the fuel pump on your Onan 5500 generator, an RV, or any other gas-powered equipment, KEMSO provides a direct-fit solution that works right out of the box. Their pumps are designed for easy installation with no modifications needed.

Visit the KEMSO website to browse their full selection of fuel pumps and find the perfect match for your generator: https://www.kemsoracing.com/

Final Tips for a Successful Replacement

  1. Take photos before you start. Document the wiring and hose routing so you can reference them during reassembly .
  2. Replace the fuel filter at the same time. A clogged filter can destroy a new fuel pump in short order .
  3. Check for air leaks. After installation, inspect all fuel line connections for leaks. Even a small air leak can cause starting problems and poor performance.
  4. Run the generator under load. After the repair, let the generator run for 30 minutes with a load applied to verify everything is working correctly.
  5. Keep spare parts on hand. Having a spare fuel pump and filter in your RV toolkit can save your trip if the pump fails on the road.

Replacing the fuel pump on your Onan 5500 generator is a manageable DIY project that will restore reliable power when you need it most. With the right parts and a little patience, you can have your generator running like new again.

For a high-quality, lifetime-warranted replacement fuel pump, check out KEMSO at https://www.kemsoracing.com/.


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