ONAN known problems but no remedy

[SuperBoar]

There are lots of strings on this forum about Onan generators and probably 95% of them are because ethanol based gasoline was left in the generator fuel system. Onan has known about this problem for years and done nothing except to tell people to run their generator, whether it is needed or not.

It would not be rocket science to develop a system for when the generator is stopped, the fuel could be drained back into the storage tank. Draining the fuel pump might be a bit elaborate, but draining the float bowl automatically would be simple.

At the VERY LEAST, Onan could have a fuel cut off valve like most lawn mowers, so the system could be sucked dry at shut down. Again at the very least, how about a useful end user manual?

Or even better, how about coach manufacturers use a generator design from this century.

[16ACE27]

Originally Posted by SuperBoar

There are lots of strings on this forum about Onan generators and probably 95% of them are because ethanol based gasoline was left in the generator fuel system. Onan has known about this problem for years and done nothing except to tell people to run their generator, whether it is needed or not.

It would not be rocket science to develop a system for when the generator is stopped, the fuel could be drained back into the storage tank. Draining the fuel pump might be a bit elaborate, but draining the float bowl automatically would be simple.

At the VERY LEAST, Onan could have a fuel cut off valve like most lawn mowers, so the system could be sucked dry at shut down. Again at the very least, how about a useful end user manual?


Small engice
Or even better, how about coach manufacturers use a generator design from this century.

Do you not find the commonly available/downloadable user manual usable?

Building an RV is all about cost. Do you know of another generator manufacturer that provides ready to bolt in RV generators at the same cost point as Onan/Cumins that are just as reliable?

Small ICE technology has not changed a whole lot in the last century, but Onan engines are state of the art, OHV, in some cases fuel injected, and as reliable as any other small ICE. All small ICE suffer from stagnation with ethanol fuel - follow the maintenance directions in the owners manual and your problems will be solved; including corrosion issues in the generator stator due to moisture.

[EA37TS]

Exercise the generator as recommended.

If you don’t like Oman, quit buying RV’s that have them installed. Very simple fix.

3 Onan generators over 15 years with no problems. But then I’m smart enough to read the manual and follow the recommendations.

[DavidEM]

Carbureted engines which are the cause of almost all of the problems with ethanol in gasoline are definitely not state of the art. Electronic fuel injection virtually eliminates ethanol/water problems because the fuel system is totally sealed with EFI.

Cummins does produce a state of the art, 21st century engine- the one on the new QG 2800i, an EFI engine and an inverter technology generator. It is quieter, uses less fuel at part load, should last longer and never have ethanol gasoline problems.

When the 2800i was introduced a couple of years ago, Cummins said a 4000i would be forthcoming. Not so far.

David

[dkoldman]

BEFORE, buying my RV and from reading all kinds of comments on forums, the Onan Generator, Hydraulic Jacks, and Slides were my biggest fears. Not sure why I was so scared of the noise and rhetoric as all of them came with Warranties, Manuals, Direct Mfg Customer Service and the RV Mfg Customer Support. I think the Onan Generator actually had a 3 year warranty. Needless to say I have maintained EVERYTHING by the book, and by those member recommendations on forums that I have learned that have been there and done that. Never an issue (knock on wood). The so called Green Monster is actually my Green Friend. Maybe I am just misguided; but you know what gives me a thrill of joy every time I go camping... Auto leveling coach, letting out the slide, and firing up the generator Weather permitting, more often than not; I forgo a site with full hookups saving a little in favor of 2 hours every day on my genny. If you have a good AGS, it will take care of a lot of stuff the manual requires, just service the oil and filter at the right intervals and level instructed by Onan.

[javelin]

I purchased my 2013 ACE new in Fall of 2012 and initially my 4KW Onan gen had some hard starting issues until I finally tweaked the choke tension spring adjustment. That was about 10 years ago now and I have to confess to being very lucky that it starts and runs like a top to this day (knock on wood). Since the DW and I are seasonal campers only (May to October) the Onan sits all Winter without any exercise (typically -10 to -40 F here in Alberta). During the camping season I only exercise the gen for 2 hours a month religiously (sometimes twice a month on occasion) under approx half load, using an electric heater we carry with us as the load; sometimes using the main A/C as a load while parked if it is hot outside. Usually the dash A/C is adequate for most of our trips in the northern states and Canada so we don’t run the gen while driving typically (this configuration has a reputation of gen quitting while driving from overheating, but we never need to do that anyway). I do make a point of treating the ACE gas tank with a little extra measured shot of Stabil gas extender in Fall (maybe 1.5 times the specified amount for the remaining estimated gas level left in the tank) and run it through the system on the final gen and coach engine run before “hibernation”. All batteries come out of the coach for Winter and get monthly charges; cleaned, watered and re-installed in Spring. I guess there is enough fresh fuel cycling through the tank and gen during the Summer months to keep the gen carb clean and starting/running well under load so far. Go figure; must have a horse shoe I never noticed.

[Lt Keefer]

My Onan generator is the most reliable small engine I own. Start every time and always produces electricity. Now that I say that it will probably crap out.

[dkoldman]

Originally Posted by SuperBoar

There are lots of strings on this forum about Onan generators and probably 95% of them are because ethanol based gasoline was left in the generator fuel system. Onan has known about this problem for years and done nothing except to tell people to run their generator, whether it is needed or not.

It would not be rocket science to develop a system for when the generator is stopped, the fuel could be drained back into the storage tank. Draining the fuel pump might be a bit elaborate, but draining the float bowl automatically would be simple.

At the VERY LEAST, Onan could have a fuel cut off valve like most lawn mowers, so the system could be sucked dry at shut down. Again at the very least, how about a useful end user manual?

Or even better, how about coach manufacturers use a generator design from this century.

I am attaching a Onan Operators Manual, because for my 5500, there is no scenario where the system is run dry as you state. Even if you intend for long term storage ( 120 days or longer) you are to use fuel stabilizers and run it long enough (30 min) to get it throughout the system. Spray an engine defogger in air filter compartment. See section 3.15