Genset won't keep running

bsiemens wrote:
Hope someone has an answer before I shell out money for ANOTHER new carborator. Genset didn't run when I bought my 2014 Winnagago Sighseer, No problem got it a good price and expected to put some money in it. $300 dollars for a carborator and the genset is running perfectly. That was 2 years ago. I start and exercise the genset every month for at least 45- 60 minutes. Last time out genset sarts and runs fine but after about 15 miutes it begins to back fire spit and quits. At first this was only under a load such as AC running. Now it has begun this back fire without being under a load. An RV repairman told me that the carborator was bad again because I should have put in a gas cut off. He said that gas left standing in carb deteriorates the carb and is the cause of the problem. Ever hear of this? I sure hate to shell out for another carborator so soon. I really don't know anything about these genertors but the rest of the coach is perfect.

Doesn't sound like your problem, with it running for that long, but I just recently removed and cleaned out two small engine carbs with great success, when they failed to run at all. Just be sure it's getting fuel first and try hanging a hose into a milk jug of gasoline, to bypass the fuel tank and input hose.

I had the exact identical problem on my Onan 5500.

Discovered it has two fuel filters, one in front of the carb and one underneath in front of the fuel pump.

When I pulled the lower one, out came a bit of water with the fuel (it's the lowest point in the system), shook it out, reinstalled and the problem was solved immediately.

David

mmccray100 wrote:
Do any or all of these responses take into consideration the the RV in question has an on-board genset and gets it's fuel from the RV fuel tank, not a dedicated tank? If I have a full 75 gallon tank, do I put 150 ounces of Seafoam in it?
My 99 Winnebago is exhibiting similar problems, but without the back firing. It will run for about 30 minutes before reving for a few seconds and shuts down. I tuned it up with plugs, filters (fuel & oil) and changed the oil. Prior to the tune-up it wouldn't start at all. At least it runs long enough to make my coffee in the AM!lol
Nobody would confuse me with a real mechanic, bu I am capable of minor fixes that don't involve a serious tear-down.
Thanks for any help
Mike

what engine do you have, and is it fuel injected?

The carb is very simple. Just take it apart and clean it.

If it runs nicely for fifteen minutes, it's not the carb, but almost certainly something heat related. If there's a little electric fuel pump, they're somewhat famous for wearing out and stopping when hot. I've also heard of ignition coils/units getting heat sensitive.

If it doesn't run well at all, it may be the carb.

Do any or all of these responses take into consideration the the RV in question has an on-board genset and gets it's fuel from the RV fuel tank, not a dedicated tank? If I have a full 75 gallon tank, do I put 150 ounces of Seafoam in it?
My 99 Winnebago is exhibiting similar problems, but without the back firing. It will run for about 30 minutes before reving for a few seconds and shuts down. I tuned it up with plugs, filters (fuel & oil) and changed the oil. Prior to the tune-up it wouldn't start at all. At least it runs long enough to make my coffee in the AM!lol
Nobody would confuse me with a real mechanic, bu I am capable of minor fixes that don't involve a serious tear-down.
Thanks for any help
Mike

Thanks for all the good tips. I have replaced the fuel filter and no change. I added two cans of sea foam to half a tank of gas, about 40 gal and ran it for about 30 minutes the first time when the generator quit and again for another 30 minutes the next day when it quit again. I realize now that starting and running once a month is not enough not to use stabalizer. I am going to try to remove the bowl from the carb and take a look. I sure can't hurt it at this point.

old ethanol gas can do bad things to a fuel system, and even after replacing a carbruetor, the old fuel in the tank and lines will carry debris into the new carb.
the fix is to run some seafoam fuel additive thru it.... it will quickly dissolve the built up gum and varnish that ethanol fuels develop so quickly when it sets.

if you know how much fuel is in the tank, add the correct amount of seafoam (2-3 oz per gallon of gas) and then run the motor long enough to insure the seafoam gets into the carb.... let it set overnight and start and run an hour or more the next day.... it will burn out all the dissolved gunk and fix the problem. any bad ethanol fuel that is left in the tank is treated, and adding fresh fuel should allow it to easily pass thru the system without a problem.


a filter is ALWAYS a requirement, but Ive never had a fuel shut-off inline of any genset Ive ever owned, and have never had a problem as the fuel set in the carb over the winter.... if its going to be a long winter, using the blue stabil will help a lot (red stabil does not work on ethanol fuels)
but the very best thing one can do to prevent bad fuel, and dirty/damaged carbs, is to use ethanol FREE fuel. you will never again have an issue unless you get a dose of dirty fuel...

and all the other small engines I have that DO have fuel shut-offs, I dont shut the fuel off.... still no problems... using clean fuel in a clean system is the only way to keep the seasonal maintenance to a bare minimum..

MrWizard wrote:
are you the least bit Handy ?

i would get 3-5gal can of gas,
a can of Sea-Foam
mix the sea foam in the gas
disconnect the fuel hose inlet to the fuel pump
connect a piece of fuel hose and put in the gas can
get generator started run until gas is gone, 4 hrs ? or more,
may have to get some fuel into carb let soak overnight
then run it it the next day, keep it running until it smooths out and runs right.

This will not work it the genset does not have a working fuel pump. Disconnect the fuel line after the pump and crank the generator. It should spit fuel.

Your SeaFoam "fix" may or may not work. A "handy" person would drop the bowl, inspect for sediment and shoot some aerosol carb cleaner through the main jet (typically the nut that holds the bowl on). It really is that simple. Just be careful when reassembling not to pinch the rubber o-ring on the bowl.

If you can get the genset to run but the RPM goes up and down, then further cleaning is required that will entail removing the carb.

I have a 96 Southwind, original Onan 5000 with the original carburetor.
I run it under load about once a month.
Have you changed the carburetor fuel filter?
Try a can of spray Seafoam. Spray it into the carburetor while it's running and leave it sit for a couple hours.
Try the simple things before buying a new carburetor
Don't use that RV repairman.