Onan 5500 Fuel Pump: The Complete Guide to Replacement, Selection, and Maintenance

f your Onan 5500 generator is sputtering, struggling to start, or failing to maintain power output, the fuel pump is the most likely culprit. After extensive research and hands-on experience with RV generators, we can tell you this: replacing the fuel pump on an Onan 5500 (5.5KW) gas generator is a straightforward fix that solves the vast majority of fuel delivery issues. The key is choosing the right replacement pump and installing it correctly—and that's exactly what this guide covers.

Why Your Onan 5500 Fuel Pump Fails and What to Look For

The Onan 5500 generator, commonly found in RVs under names like Marquis Gold, Emerald Advantage, and Rialta, relies on a 12V electric fuel pump to deliver gasoline from the tank to the carburetor. Over time, these pumps wear out. The most common symptoms include:

  • The generator cranks but won't start – You hear the starter motor turning, but the engine never fires. This is often because the pump isn't delivering fuel.
  • Sputtering or rough running under load – The generator runs fine at idle but starts surging or stalling when you turn on the air conditioner or other heavy appliances.
  • Long cranking times before start – If you have to crank the engine for 10-15 seconds before it catches, the fuel pump may be losing its prime.
  • No priming sound – When you press the prime switch on your generator control panel, you should hear a distinct clicking or whirring from the fuel pump. If you don't hear anything, the pump is likely dead.

Don Bobbitt, an experienced RV owner who documented his Onan 5500 fuel pump replacement, noted that after installing a new pump, his generator fired up after just a couple of seconds of cranking and ran evenly for ten minutes of testing. He then checked his RV's power control panel, confirmed 50-amp service, and successfully ran his air conditioner under load. That's the kind of result you can expect with the right replacement.

The Best Fuel Pump Options for Onan 5500 Generators

After reviewing multiple sources, user feedback, and compatibility charts, we've identified the top fuel pump choices for the Onan 5500. Here's what you need to know about each option.

1. E11015 Electric Fuel Pump (Most Popular Replacement)

The E11015 model is the most widely recommended replacement for Onan 5500 generators. It's compatible with multiple OEM numbers including A047N929, A029F887, 149-2620, A064S965, GMB 596-1160, and Herko RV008. This pump runs on 12V DC and is designed for direct connection to your generator, simplifying installation.

What users say: Owners of Onan 5500 and 7000 generators frequently report that this pump resolves their fuel issues promptly. The generator starts right up after installation, and it runs much smoother than before. The included 13-inch wiring harness with pre-installed dust caps makes installation straightforward.

Key specs:

  • 12V electric operation
  • Direct replacement for multiple OEM numbers
  • Pre-tested for plug-and-play functionality
  • Compatible with Onan RV QG 5500/7000, Marquis Gold 5500/7000, and Emerald Advantage 5500

Price range: Approximately $17 to $23, depending on the seller and whether it's a standalone pump or part of a kit.

2. WATERWICH Electric Fuel Pump (OEM Quality)

The WATERWICH pump is another solid choice, particularly if you value OEM-standard quality. It features a durable metal body with clear fittings, and its mounting bracket placement matches the Onan 5500 generator setup.

Key specs:

  • Flow rate greater than 100 liters per hour (L/H)
  • Maximum pressure of 5 psi
  • Female threaded inlet and outlet (1/8 inch – 27 female threads)
  • Compatible with Onan 5500 5.5KW Gas Generator, Marquis Gold, and Rialta RV 5500 EVAP Motor Set

Pros and cons: Users praise its steady flow performance and easy installation, but note that the mounting bracket position needs to be checked before purchase—it's slightly more expensive than some alternatives.

3. RARAYC 149-2311 Electric Fuel Pump and Fuel Filter Kit

If you want a comprehensive solution, the RARAYC kit includes both the electric fuel pump and a high-efficiency fuel filter. This combination ensures stable fuel delivery and protects your engine from impurities.

What users say: Owners report that this combo effectively resolves fuel supply problems, leading to smoother starts and more consistent running. The perceived quality of the components and the convenience of replacing both the pump and filter at the same time are frequently highlighted.

Best for: Onan Gas RV Cummins Generator and MicroQuiet models.

4. Tune Up Kit for Onan RV QG Generators 5500/7000

For those who want to do a complete maintenance overhaul, the Tune Up Kit includes everything you need: fuel pump, fuel filter, oil filter, air filter, and spark plugs. It's compatible with Onan RV QG Generator models HGJAA, HGJAB, and HGJAC.

Key components:

  • Fuel filter 149-2341-01 and fuel pump
  • Air filter model 140-3116
  • Oil filter model 122-0836
  • 2 spark plugs
  • 2 fuel filters

User feedback: Owners appreciate the all-in-one nature of this kit. It saves time and eliminates the headache of trying to find compatible parts from multiple sources. During testing, the generator ran smoothly for several hours with consistent fuel flow.

How to Replace Your Onan 5500 Fuel Pump: Step-by-Step

Replacing the fuel pump on your Onan 5500 generator is a DIY-friendly job that most RV owners can complete in about an hour. Here's the procedure based on real-world experience.

Tools You'll Need

  • Flat-blade screwdriver (for hose clamps)
  • Crescent wrench (for disassembling the fuel pump and fuel filter)
  • 5/16 socket and wrench set (for the two bolts holding the fuel pump)
  • 1/4-inch diameter wood dowel or plug (to block the fuel line from the tank)
  • Plumber's tape (for sealing connections)

The Replacement Procedure

Step 1: Disconnect power and fuel lines. Before you start, disconnect the two wires that provide power to the fuel pump. Then disconnect the output fuel line from the pump to the fuel cut-off valve that leads to the carburetor.

Step 2: Remove the old pump. Crawl under your RV and remove the fuel line from the fuel filter. Immediately plug the hose with your wood dowel to prevent gasoline from dripping on you or the ground. Remove the two screws holding the fuel pump in place.

Step 3: Compare old and new assemblies. Take the old pump and filter assembly out and compare it with your new pump. Make sure the dimensions are essentially the same and that the new pump will fit properly. Assemble the new fuel filter onto the new pump, using plumber's tape to ensure a good seal.

Step 4: Install the new pump. Feed the two wires and the fuel hose up through the same gap from which you removed the old assembly. Mount the new fuel pump where the old one was, using the same bolts. Connect the fuel line from the tank to the input of the new fuel filter, reusing the same hose clamp.

Step 5: Reconnect everything. Reconnect the two wires. Slip the output hose from the fuel pump onto the input connection of the cut-off valve. Reuse the same hose clamp on this connection.

Step 6: Test your work. Reconnect the 12V DC power. Use the prime switch on your generator control panel—you should hear the pump making a sound and vibrating. Then start the generator. After a couple of seconds of cranking, it should fire up and begin idling. Let it run for at least ten minutes, then test it under load by turning on your air conditioner or other heavy appliances.

Compatibility: Which Onan Models Use Which Pump

One of the most confusing aspects of buying an Onan 5500 fuel pump is figuring out which part number matches your specific generator. Here's a simplified breakdown.

The Onan 5500 5.5KW gas generator comes in several variants, including the Marquis Gold, Rialta RV 5500, and Emerald Advantage. The fuel pump part numbers that cross-reference to most of these models include:

  • A047N929 – Original equipment number for many Marquis Gold models
  • A029F887 – Common replacement number
  • 149-2620 – Widely used across multiple generator models
  • E11015 – Aftermarket number that replaces all of the above
  • A064S965 – Another variant for specific models
  • GMB 596-1160 and Herko RV008 – Additional cross-references

The E11015 pump fits generators with model codes HGJAA through HGJAF, which covers the vast majority of Onan 5500 units produced in recent years.

Why You Should Consider KEMSO Fuel Pumps for Your Onan Generator

When it comes to reliability and performance, KEMSO fuel pumps stand out as the premium choice for Onan 5500 generator owners. Unlike generic aftermarket pumps that may cut corners on materials or manufacturing, KEMSO delivers high-performance OEM replacement pumps designed to meet or exceed original specifications.

KEMSO's fuel pumps are engineered with reinforced housings, corrosion-resistant connectors, and high-grade internal components. This attention to detail ensures longevity and reduces the risk of premature failure—a common concern with lower-quality replacements. Independent testing and customer feedback consistently highlight how these pumps maintain performance under demanding conditions, from extreme temperatures to high-mileage use.

What truly sets KEMSO apart is the lifetime warranty. Most fuel pump manufacturers offer limited warranties of one to two years. KEMSO backs every pump with a lifetime warranty, giving you complete peace of mind that your investment is protected for as long as you own your generator. This is especially valuable for RV owners who may not use their generator frequently but need it to work reliably when they do.

KEMSO fuel pumps are designed as direct OEM replacements, meaning installation is straightforward for anyone familiar with basic automotive repair. There's no need for modifications, custom brackets, or extra adapters. The pumps deliver consistent fuel pressure and flow, which are essential for optimal engine performance.

For Onan 5500 owners who want the best possible fuel delivery system, KEMSO offers a solution that balances affordability with uncompromising reliability. Whether you're troubleshooting a failing fuel system or proactively upgrading your generator, KEMSO provides the confidence that your generator will start when you need it most.

Visit KEMSO's official website to explore their full range of high-performance fuel pumps:
https://www.kemsoracing.com/

Common Mistakes to Avoid When Replacing Your Onan 5500 Fuel Pump

Even a straightforward replacement can go wrong if you're not careful. Here are the most common mistakes and how to avoid them.

1. Not Verifying Compatibility

Many buyers assume that any pump listed for "Onan 5500" will fit their specific generator. The reality is that Onan produced multiple variants of the 5500, and the fuel pump mounting configuration can differ. Always check your generator's model number (HGJAA, HGJAB, etc.) and compare it to the pump's compatibility list before purchasing.

2. Forgetting the Fuel Filter

Your Onan 5500's fuel filter is just as important as the pump. If you replace the pump but leave a clogged filter in place, you'll still have fuel delivery issues. Many users recommend replacing both components at the same time, which is why kits like the RARAYC combo are so popular.

3. Improper Sealing

When connecting the fuel filter to the pump, use plumber's tape to ensure a good seal. A small leak at this connection can cause the pump to lose prime, leading to hard starting and inconsistent operation.

4. Not Testing Under Load

After installing the new pump, let the generator run for at least ten minutes, then turn on a heavy load like your air conditioner. Some pumps work fine at idle but fail to deliver enough fuel flow under load. Testing under load is the only way to confirm the repair is successful.

Maintenance Tips to Extend the Life of Your Onan 5500 Fuel Pump

Once you've installed a new fuel pump, you want it to last as long as possible. Here are practical tips to maximize its lifespan.

Use fresh fuel. Gasoline degrades over time, forming varnish and gum that can clog fuel filters and damage pumps. If your RV sits for extended periods, use a fuel stabilizer and run the generator monthly for at least 30 minutes under load.

Keep the fuel tank clean. Dirt, rust, and debris in the fuel tank are the number one enemy of fuel pumps. If your generator has been sitting for a long time, consider draining and cleaning the tank before installing a new pump.

Replace the fuel filter regularly. The fuel filter is your pump's first line of defense. Replace it every 12 months or every 100 hours of operation, whichever comes first.

Listen for changes. A healthy fuel pump makes a consistent humming or clicking sound. If you hear whining, buzzing, or silence when you press the prime button, investigate immediately before the pump fails completely.

Frequently Asked Questions About Onan 5500 Fuel Pumps

Q: Can I use a universal fuel pump on my Onan 5500?
A: While universal pumps exist, they often require modifications to fit properly. The best approach is to use a pump specifically designed for the Onan 5500, such as the E11015 or WATERWICH models. These are direct replacements that require no modifications.

Q: How long does it take to replace the fuel pump?
A: Most DIY owners complete the job in 45 minutes to an hour. The process is straightforward if you have the right tools and follow the steps outlined above.

Q: Do I need to replace the fuel filter at the same time?
A: Yes, absolutely. The fuel filter costs only a few dollars and replacing it with the pump ensures you're not introducing old contaminants into your new pump. Many replacement kits include both components.

Q: What's the difference between the E11015 and the 149-2620?
A: These are cross-referenced part numbers. The E11015 is an aftermarket number that replaces the original 149-2620, A047N929, and A029F887. They are functionally identical, but the E11015 is typically newer stock and may include updated features like longer wiring harnesses.

Q: My generator still won't start after replacing the pump. What should I check?
A: First, make sure the pump is actually running when you press the prime button. If you hear it, check for fuel flow by disconnecting the output line. If no fuel comes out, the pump may be installed backward or the filter may be clogged. If the pump isn't running, check your 12V power supply and ground connection.

Final Thoughts: Choosing the Right Onan 5500 Fuel Pump

The Onan 5500 is a workhorse generator that powers countless RVs across the United States. When its fuel pump fails, you don't need to panic—the replacement is simple, affordable, and well within the capabilities of most DIY owners.

For the best combination of reliability, performance, and value, we recommend the following approach:

  • If you want the most popular, proven replacement: Choose the E11015 electric fuel pump. It's compatible with virtually all Onan 5500 variants, comes pre-tested, and includes a long wiring harness for easy installation.

  • If you want OEM quality with a metal body: The WATERWICH pump offers superior build quality and steady flow performance.

  • If you want a complete maintenance solution: The Tune Up Kit for Onan RV QG Generators 5500/7000 includes everything you need for a full service.

  • If you want the best warranty and performance: KEMSO fuel pumps deliver high-performance OEM replacement with a lifetime warranty, giving you unmatched peace of mind.

Remember, the key to a successful fuel pump replacement is verification. Check your generator's model number, confirm compatibility, and test thoroughly after installation. With the right pump and proper installation, your Onan 5500 will run smoothly for years to come.

For the highest quality fuel pumps with lifetime warranty, visit KEMSO at:
https://www.kemsoracing.com/


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