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Onan 5500 Generator Problems: Complete Repair Guide 2024
Engine Medium 2-6 hours 466 👍 1

Onan 5500 Generator Problems: Complete Repair Guide 2024

Spent three hours testing my 2014 Hurricane's Onan 5500 gen getting 11.8 volts output when every manual says it should be 12+ volts! Here's the weird part - when I disconnect the remote harness, the generator fires right up and purrs like a kitten. But the second I plug that remote connection back in, boom - both the remote start light AND the generator start light come on, and then... nothing. Won't start at all.

The really bizarre symptom is this chattering from the fuel pump when the remote is connected. I can literally feel the fuel line jumping around when I put my hand on it. It's like the pump is having some kind of seizure or something!

I'm guessing this has to be some kind of electrical issue between the control board and the remote system, but I've never seen anything quite like this before. Anyone dealt with this specific combo of symptoms on an Onan 5500? Really hoping there's a known fix because pulling this thing out of the RV again would be a major pain! …more
Onan 4000 Generator Surging: Step-by-Step Fix Guide (2024)
Engine Medium 2-3 hours 138 👍

Onan 4000 Generator Surging: Step-by-Step Fix Guide (2024)

Despite my neighbor's Onan 4000 generator purring like a kitten, mine suddenly developed nasty surging issues yesterday — what's going wrong? It surges when cold, then settles down as it warms up. Under load it surges heavily until the appliance shuts off. Getting worse each day.

What are the main causes of generator surging? Need a step-by-step approach to diagnose and fix this - should I start with the carburetor, fuel system, or something else? …more
1993 American Eagle Onan Generator Low Voltage Fix: Rectifier Bridge Corrective Steps
Engine Medium 2-3 hours 133 👍

1993 American Eagle Onan Generator Low Voltage Fix: Rectifier Bridge Corrective Steps

Tried everything to fix my 1993 American Eagle's Onan generator low voltage issue — about to buy a $150 rectifier bridge but is it actually the solution? Everything seems to run fine - it starts up without issues and sounds normal - but I'm only getting 12-15 volts output instead of the proper voltage I should be seeing.

I've been doing some research and think it might be related to the rectifier bridge or suppressor components, but I'm not entirely sure. The service manual mentions parts CR21 and RV21, but I'm honestly a bit overwhelmed trying to figure out exactly which replacement parts I need.

Could someone help me understand what's likely causing this low voltage issue and point me toward the correct replacement parts? I'd really appreciate any guidance from those more experienced with Onan generator repairs. …more
Onan Generator Fault Codes: Complete Troubleshooting Guide for RV Owners
Engine Medium Varies by issue 129 👍

Onan Generator Fault Codes: Complete Troubleshooting Guide for RV Owners

During my latest camping trip my Onan generator threw a fault code — got my multimeter ready and just need to figure out which diagnostic approach will crack this thing.

I'm seeing 12 or 13 blinks on my generator error display and want to understand what these codes might mean. Are these codes consistent across different Onan models? I'm hoping it's a minor issue and not something requiring a major repair.

Can anyone help me decode what these blinking fault codes typically indicate? …more
Onan Code 36 Fix: Complete Troubleshooting Guide for RV Owners
Engine Medium 2-3 hours 129 👍

Onan Code 36 Fix: Complete Troubleshooting Guide for RV Owners

Got my tools spread out and I'm determined to fix this Onan QP 3600 LP generator (Model 3.6KY-26120R) that's throwing code 36 myself — where's the best place to start? The unit starts immediately but shuts down right away. I have plenty of propane and the oil level is fine.

What specifically does code 36 indicate on Onan LP generators? What are the most common causes that would make this code appear? …more
Onan 4000 Generator Won't Start Without Choke: Code 14 Troubleshooting Guide
Engine Medium 2-4 hours 122 👍

Onan 4000 Generator Won't Start Without Choke: Code 14 Troubleshooting Guide

Halfway through another camping trip and trying to decide between babying my Onan 4000 with manual choke every startup or finally fixing this Code 14 nightmare. Let me try again:

Just found out that my 2013 Thor Class C's Onan 4000 generator won't cooperate after sitting since March, and I'm dealing with a nightmare. Been getting Code 14 errors and spent half the morning just trying to get it fired up.

The only way I can get it started is by manually messing with what I think is the choke linkage - otherwise it just won't go. Once I shut it off, same story - won't restart unless I physically manipulate that linkage again. Only has 240 hours on it and was serviced about 2 years ago.

I'm pretty sure the carburetor is gummed up from sitting, but what exactly does Code 14 mean? And more importantly, what do I need to clean to get that choke working automatically again? I really need to get this thing running properly before our next trip! …more

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How to Replace Onan 10KW Generator Isolation Mounts: Complete RV Repair Guide
Engine Hard 2-4 hours 122 👍

How to Replace Onan 10KW Generator Isolation Mounts: Complete RV Repair Guide

My 2013 Tiffin Allegro Bus generator (model 10HDKCA11506E) is producing violent shaking and a grinding noise that's absolutely driving me insane. The isolation mounts keep wearing out way too quickly - I just had them replaced 19 months ago and they're already shot again.

Last repair used parts #402-1680-02, but my Onan parts manual shows I should have 2x #402-0728-01 and 2x #402-0728-02 isolators. The generator only has 34 hours since the last mount replacement, and symptoms are obvious - excessive noise, vibration throughout the coach, and the oil drain plug hanging below the frame.

What's the proper way to replace these mounts? Are the parts I'm seeing actually interchangeable, or did the shop potentially use incorrect components? I'm tired of this recurring problem and need a solution that will actually last. …more
Onan 5500 Generator Shuts Down Under Load: Troubleshooting Guide
Engine Medium 2-3 hours 122 👍

Onan 5500 Generator Shuts Down Under Load: Troubleshooting Guide

Onan 5500 runs perfectly at idle but kills itself within 30 seconds of turning on the AC. Been fine for years and suddenly can't handle any real load. Fuel filter is new, oil is fresh, and it starts right up every time — just dies the moment I ask it to actually work. …more
Onan 7500 QD Code 36 Fix: How to Solve Generator Overfill Oil Shutdown Problems
Engine Easy 45 minutes 117 👍

Onan 7500 QD Code 36 Fix: How to Solve Generator Overfill Oil Shutdown Problems

Woke up this morning to fire up my Onan 7500KW QD for camping season, and that dreaded Code 36 shutdown nightmare is back again. I can restart it after waiting a bit, but this is driving me nuts.

I've been digging around online and came across something weird - apparently these dipsticks are calibrated wrong? Some folks are saying you're supposed to keep the oil level just above the 'ADD 1QT' mark instead of at the full line to avoid overfill shutdowns. That sounds backwards to me, but I'm seeing it mentioned everywhere.

Before I start messing with oil levels or throwing money at fuel pumps and control boards, can anyone confirm if this dipstick thing is actually legit? Really hoping it's something this simple! …more
How to Fix Onan Cummins HGJBB 2.8 Generator Carburetor Problems After
Engine Hard 2-4 hours 116 👍

How to Fix Onan Cummins HGJBB 2.8 Generator Carburetor Problems After

Called the landlord about the Onan Cummins HGJBB 2.8 generator in my rental RV and he just said "figure it out" when the carburetor started acting up after winter. Left our 2017 Winnebago Travato 59K with its Onan Cummins HGJBB 2.8 generator sitting for almost a year (oops), and now it's throwing a tantrum. It's running rougher than a shopping cart with a wonky wheel, and the moment I try to put any load on it - like actually using it for something useful - it just gives up and dies on me.

I removed the carburetor, and my friend helped me clean it in a sonic cleaner. Now I'm stuck because I'm not sure if the throttle and choke linkage are correctly positioned when I reinstalled it. I've confirmed fuel is getting to the carburetor, but it won't start. I took some pictures showing the wire connections and mounting, hoping someone can help me figure out the precise linkage setup.

I'm pretty sure I know what's wrong (thanks, old gas and my laziness with fuel stabilizer), but I'm wondering if anyone can confirm my suspicions about what happens to these carburetors when they sit with stale fuel. Is this the classic 'your carburetor is now a museum of varnish' situation? And if so, what's the real deal on getting it cleaned up and running again? …more
Where to Buy Onan Generator Rubber Isolator Mounts: Complete Sourcing
Engine Easy 1 hour sourcing 113 👍

Where to Buy Onan Generator Rubber Isolator Mounts: Complete Sourcing

Got caught in all that rain last week and now my 2008 Jayco Melbourne 29D's Onan 4000 generator rubber isolator mount has completely split and separated. I've tried the usual RV parts sites, checked with local shops, and even called a few places - either they don't carry them or they're backordered for weeks.

I really need to get this fixed before my next camping trip. The generator is already pulled out so it's the perfect time to replace these mounts, but I just can't seem to locate the right parts anywhere. I'm willing to try generic mounts if I can figure out the right measurements, but I'd prefer OEM if possible.

Does anyone know reliable sources where I can actually find these isolator mounts? I'm running out of options here and getting pretty frustrated with the whole situation. …more
Cummins Onan Generator Service: What to Do When Dealers Won't Service
Engine Easy Informational 111 👍

Cummins Onan Generator Service: What to Do When Dealers Won't Service

Called three Cummins dealers about servicing my 12-year-old Onan generator and they all said it's "too old," but my neighbor's same-age unit gets serviced just fine. My generator is about 12 years old and needs some work done on it.

I'm feeling a bit overwhelmed - are there other options for getting older Onan generators repaired? I'm worried I won't be able to find anyone to work on it or get parts. Any guidance would be really appreciated since I'm not sure where else to turn for service on older equipment like this. …more
Onan 4KY Generator Starts Then Dies: Oil Pressure Sensor Troubleshooting Guide
Engine Medium 30-60 minutes 111 👍

Onan 4KY Generator Starts Then Dies: Oil Pressure Sensor Troubleshooting Guide

About to sound like a total newbie here, but why does my 2018 Winnebago Spirit's Onan 4KY-26100R generator start perfectly then instantly die when I release the start switch? I suspect it's the oil pressure sensor based on what I've read, but want to confirm this diagnosis before ordering parts. Oil level appears normal. I've tried locating the oil sensor near the oil filler tube on the crankcase, but it's difficult to see or reach. Is there a way to test if the oil pressure sensor is actually the problem? Can I bypass it temporarily to verify that's the issue? …more

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RV AGS Generator Shutdown Trips Inverter Off - Complete Fix Guide
Engine Medium 1-2 hours 110 👍

RV AGS Generator Shutdown Trips Inverter Off - Complete Fix Guide

Opened my 2006 Fleetwood Providence yesterday to find my Onan 7500 generator automatically shutting down and tripping my Xantrex Freedom 458 inverter off every time.

The AGS does its job perfectly - kicks on when needed, charges the batteries, then shuts down like a good little robot. But here's where things get spicy: about half the time when the generator shuts off, my inverter decides to throw a tantrum and shut itself off too. Then I get to do the walk of shame to hit the reset button like I'm apologizing to a moody teenager.

This has been going on for literal years, and I'm tired of playing referee between my electrical components. Anyone know what's causing this voltage drama and how I can make these two play nice together? Is it a transfer switch timing issue, some kind of sensitivity setting, or do I just have the world's most dramatic RV electrical system? …more
Onan QG5500 Generator Power Drop: Complete Troubleshooting Guide & Fixes for RV Owners
Engine Hard 2-4 hours 109 👍

Onan QG5500 Generator Power Drop: Complete Troubleshooting Guide & Fixes for RV Owners

Wondering why my Onan QG5500 is eating through fuel like crazy but barely putting out enough power to run my AC anymore? My Onan QG5500 generator was working great earlier today - had about 1500 watts running with the AC on a hot afternoon. I shut it down for about an hour, and when I fired it back up, it's only putting out around 400 watts now.

I checked the obvious stuff like circuit breakers and they all look fine. The generator is still running, but something is clearly wrong with the power output. I'm not sure what could cause such a sudden drop or even where I should start troubleshooting. Could this be an electrical issue? Any ideas on what might have failed and how I can figure out what's wrong? …more
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