Community Forums

DaveandPatty · 04-29-2014, 01:32 PM

This may seem like a basic question, but I need to ask before I mess something up. I have a 29 foot coachman class c. I want to change fuel filter on the onan gen, so I am removed the fuel filter. No gas came out of the line from the gas tank. My gas tank is full, I just filled it. There was some gas on in the filter and some gas in engine side of line.
My thinking would tell me, that when I removed the filter gas should have pored from the line. Before I do something stupid like put an air compressor to line, I'd like some advice.
Thanks
Dave

bdpreece · 04-29-2014, 02:14 PM

Don't think I would be worried. Without the model and year of the generator I can't give you an absolute answer but on many units the electric fuel pump and or a fuel solenoid will be between the tank and the fuel filter therefor no fuel will escape when changing the filter. Other option would be that you have less than 1/4 tank of fuel so the pickup tube is above the fuel.

Skip426 · 04-29-2014, 02:22 PM

The fuel pick up for the gen set , enters the tank from the top and is set in the tank to stop picking up fuel if the level is below a 1/4 tank; so possibilities are.
1. fuel level in tank below pick up.
2. gen set not run for an extended period , and pump/filter siphoned back into tank.
JMHO. replace filter , start gen set , if after an extended crank time the gen set won't run , then you may have a problem.
And I see someone types faster than I do.

Elf111 · 04-29-2014, 02:55 PM

Don't put pressure to the line yet, try putting the new filter on and see if it will start. Don't fix it if it isn't broken.

Phobos · 04-29-2014, 08:51 PM

Mine loses it's prime all the time when it sets. Sometimes it's takes a while for the electric fuel pump to pickup the fuel and get it to the genset carburetor.
Last time I changed the fuel filter on ours, it was almost completely dry of gasoline.

You may have a different rig, but I would guess they are all setup about the same.

Phobos · 04-29-2014, 08:59 PM

I might also mention that the 1/4 tank pickup thing applies to most coaches. Not all are setup like that. I have no idea which ones are and aren't except for ours which has a tee in the main line going to the engine.

I assumed mine was setup in the top of the tank until last year when I replaced all of the 30+ rubber hoses back there. To my surprise, there was no extra hole in the tank for the generator pickup, and the genset supply ran to the tee cut in line that I mentioned before.
It's a cheap way of doing things, and I suspect it isn't a very common practice at all.
I doubt it's your case, and I just threw this out there for everyone to know that not all coach builders went the extra step.

DaveandPatty · 04-30-2014, 06:52 AM

All good advise, thank you. As I said tank is full, I forgot to mention it is a 1995 model and generator has not been run in awhile. Will report back with results

Elf111 · 04-30-2014, 04:32 PM

Not sure what awhile is but if it's been setting for a long time the carburetor may be gummed up with old fuel. When we bought our mh we were told the generator worked but it wouldn't start I took the carb off and soaked it in solvent to clean out the old fuel and gunk. I got lucky the gaskets were not torn so I reused them with a little grey silicone and it fired right up. After you get it running run it under a light load for a while then increase the load and run it for a long time like all day, these things need to be ran setting without use is the worse thing you can do to it.

DaveandPatty · 05-01-2014, 07:18 AM

Thanks, I went through same thing. I've never seen this one run for more then 2-3 minutes. Its really never been an issue because we always camp were there is electric hookups. I just want to get it working. Before I go the route of removing the carb, I am going to try some SeaFoam directly into carb and let sit overnight or two. Then the new filter, and spark plug.

DaveandPatty · 05-27-2014, 06:56 AM

it is a microlite 4000 so, I put on new fuel filter, new spark plug,and it just cranks There is no fuel getting to it. I have a full tank of gas.
I have had this gen running but never longer then 2 or 3 mins. I thought maybe was clogged filter. But it is not getting fuel from the tank. Where to next??

Elf111 · 05-27-2014, 07:12 AM

You said you changed the spark plug is it a single cylinder engine? I have the onan emerald plus witch is a two cylinder number two is tuff to get to. I think I would make sure the fuel pump is working ( pull fuel line off carb and crank it it should pump gas) if not sounds like you need a fuel pump or your line from the tank is plugged or crushed.

Mich F · 05-27-2014, 07:18 AM

Quote:

Originally Posted by DaveandPatty

it is a microlite 4000 so, I put on new fuel filter, new spark plug,and it just cranks There is no fuel getting to it. I have a full tank of gas.
I have had this gen running but never longer then 2 or 3 mins. I thought maybe was clogged filter. But it is not getting fuel from the tank. Where to next??

Have you tried priming it first ? If you push your stop or off button on your generator on/off switch , that should prime the generator. You might also try turning on the motor home, which should help the house battery in turning over the generator.
If the carb is the issue, I believe Onan says, they are not supposed to be rebuilt, but replaced .

mel s · 05-27-2014, 07:40 AM

Quote:

Originally Posted by DaveandPatty

removed the fuel filter. No gas came out of the line from the gas tank. My gas tank is full, I just filled it. There was some gas on in the filter and some gas in engine side of line.
My thinking would tell me, that when I removed the filter gas should have pored from the line.
Dave

Quote:

Originally Posted by DaveandPatty

it just cranks There is no fuel getting to it. I have a full tank of gas.
I have had this gen running but never longer then 2 or 3 mins. I thought maybe was clogged filter. But it is not getting fuel from the tank. Where to next??

Dave
Fuel does not need to "pour from the line" for the Onan to run..... (the Onan draws/pumps the fuel out of the fuel tank).

To find out if the fuel line is clogged, blow into the fuel line while someone listens, (at the filler neck), for bubbles in the tank at the fuel filler, (or blow air into the filler neck and see if fuel comes out of the genset end of the disconnected fuel line).

If there is a hole, crack, loose hose clamp, etc. in the fuel line FROM the tank TO the generator you may not see a fuel leak, but the pump may not be able to pump fuel because of the air leaking into the fuel line.

BTW, to verify that your generator is pumping fuel, starting and working properly, you can run a temporary fuel line/hose from a can of fuel sitting on the ground to your generator.

Mel

rvten · 05-28-2014, 08:59 AM

Unless I clamp off fuel line from MH tank. Gas will free flow a lot.
Just get a little from gen when changing fuel filter.
Also found the need to put a thread sealant on the new filter.
First time I did not and got a little drip. Removed and sealed it.