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Onan 5500 Generator Problems: Complete Repair Guide 2024
Engine Medium 2-6 hours 290 👍 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
RC7-GS Inverter AGM Battery Settings: Complete Setup Guide
Solar Batteries Medium 2-4 hours 201 👍

RC7-GS Inverter AGM Battery Settings: Complete Setup Guide

Replaced my 105Ah AGM battery and now my RC7-GS inverter charger is completely rejecting it like this capacity doesn't exist in its programming.

The charging settings only go from 125Ah up to 1000Ah, with an 'auto' option that supposedly 'learns' my battery but resets every time the low voltage cutoff trips (which feels like cheating, honestly). I'm worried about undercharging or cooking my expensive new AGMs if I pick the wrong setting.

Oh, and while we're talking about things that don't work as advertised - the generator auto-start feature might as well be a myth. Can't even manually start the generator from the RC7 panel. At this point I'm wondering if I should have just stuck with my old setup that actually worked! Anyone know what I'm doing wrong here? …more
Onan 4000 Generator Surging: Step-by-Step Fix Guide (2024)
Engine Medium 2-3 hours 105 👍

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 105 👍

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 5500 Generator Shuts Down Under Load: Troubleshooting Guide
Engine Medium 2-3 hours 98 👍

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 Code 36 Fix: Complete Troubleshooting Guide for RV Owners
Engine Medium 2-3 hours 98 👍

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

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Onan Generator Fault Codes: Complete Troubleshooting Guide for RV Owners
Engine Medium Varies by issue 94 👍

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 4000 Generator Won't Start Without Choke: Code 14 Troubleshooting Guide
Engine Medium 2-4 hours 92 👍

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
Onan 5500 Generator Tune-Up Guide: Best Aftermarket Parts & Filters 20
Engine Medium 2 hours 90 👍

Onan 5500 Generator Tune-Up Guide: Best Aftermarket Parts & Filters 20

Before my last camping trip when I tried to order replacement parts, I discovered that finding genuine OEM components for my Onan 5500 generator has become nearly impossible. The Cummins website has been showing most tune-up components as out of stock for months now, and when I do find supposedly "official" Onan oil filters online, many retailers are substituting generic filters that may not meet the same specifications.

I've been researching alternatives and I'm particularly concerned about getting the right oil filter and spark plugs. For the oil filter, I've seen conflicting information about whether aftermarket options like Wix filters are truly compatible - some sources mention the 57398 but I've read mixed reviews about fitment issues. For spark plugs, my current ones are NGK BPR4EY, and I've heard the NGK 3432 might be equivalent, but I want to make sure before ordering.

I'm also planning to stick with zinc-containing oil like Rotella T6 15w40 since I know air-cooled engines need the extra protection, but I'd love confirmation that I'm on the right track with quality aftermarket parts that won't compromise my generator's performance. What specific part numbers and brands would you recommend for a reliable tune-up when OEM parts aren't available? …more
How to Replace Onan 10KW Generator Isolation Mounts: Complete RV Repair Guide
Engine Hard 2-4 hours 90 👍

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 7000 Generator Low Voltage to Fuel Pump: Complete Repair Guide
Engine Medium 2-3 hours 89 👍

Onan 7000 Generator Low Voltage to Fuel Pump: Complete Repair Guide

Our Onan 7000 Marquis generator is hitting us with low voltage to the fuel pump for the third time this season and I'm done with guessing games. When I check the voltage at the fuel pump, I'm only getting 9V instead of 12V, and surprise surprise - it won't start. But here's the kicker - if I jump 12V directly to the pump, the thing fires right up and runs like a champ.

Obviously there's a voltage drop happening somewhere between the control board and the fuel pump, but I'm not sure where to start looking. Could be corroded connections, maybe the control board itself is going bad, or some wiring issue in the fuel pump circuit? Anyone dealt with this before and know the most common culprits? …more
How to Fix Onan QD3200 Diesel Generator Fuel Leak Behind Air Filter
Engine Medium 1-3 hours 87 👍

How to Fix Onan QD3200 Diesel Generator Fuel Leak Behind Air Filter

According to Murphy's Law, my Onan QD3200 generator is doing something bizarre — it's leaking diesel fuel from behind the air filter instead of where you'd normally expect fuel leaks. The fuel appears to be coming from somewhere behind the air filter box, and I'm worried about making things worse if I don't diagnose this properly. I've shut everything down for now because I'm nervous about safety issues.

I need to know the safest way to trace where this leak is actually coming from without creating a fire hazard or damaging anything. What are the most likely culprits in that area, and what's the proper procedure to identify the exact source? I want to make sure I approach this methodically rather than just poking around and potentially making the problem worse. …more
How to Fix Onan Cummins HGJBB 2.8 Generator Carburetor Problems After
Engine Hard 2-4 hours 84 👍

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

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Onan 7500 QD Code 36 Fix: How to Solve Generator Overfill Oil Shutdown Problems
Engine Easy 45 minutes 82 👍

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
Where to Buy Onan Generator Rubber Isolator Mounts: Complete Sourcing
Engine Easy 1 hour sourcing 81 👍

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
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