When I bought this motorhome over 2 years ago I was told the generator ran but the tank was too low on gas to run it. At the time it wasn't a deal breaker if it didn't, so I drove it home. Once I put enough fuel in the tank I would push the start button on the dash and it would start right up then make a big belch, then quit. Several time this was the case, so I just left it be since there many other things to work on and the club we belong to has full hookups. The other day I got the bug to work on it so I pulled it out on the slides and tried the same thing, the only thing it would do then was just make the solenoid rattle noise. I looked at all cable ends and cleaned them, retried and still wouldn't start. The next thing was to use a separate battery which I connected and the thing started right up and even powered one of the air conditioners. It runs somewhat rough and I ordered a new muffler being one end is missing. I also will get a carb kit if cleaning the main jet wont clear up the rough running. I tried looking around underneath last night to see if there were and broken cables or dirty connections but, I could find none. I did find that is if I connect the positive cable from the gen to the positive on the chassis battery instead of the block terminal where it was it starts every time. I have no coach batteries hooked up at this time and the cables from them I took out. Do I need the coach batteries for the generator to start or is there a switch I should be moving ?

Do not know your rig but my southwind starts the genny off the house batteries not the chassis

that might be how its supposed to be on mine too, mines too old I think to find any info, thanks

Ours also uses house batteries to start the genset. When we first bought our coach, we also took it for granted that the genset would run....it didn't. It would turn over, but would not run. After some serious diagnosing, I came to the conclusion that the carb was varnished from old gas and the needle valve was stopped up. Run some SeaFoam through thorugh the gas and see if that cleans the carb enough to get it running good. If you have to, disassmble the bowl/needle valve and soak them in straight Seafoam for about an hour and then clean them with a stiff brush before replacing. Onan will tell you that you should replace the carb, but you can take it apart and reassemble successfully.Then run Seafoam in every tank to treat and clean the fuel system from all that crappy gasoline we are forced to buy now. Unless you travel a lot, that's a bunch of gasoline just sitting in a tank going bad if not treated with something.

10forty2 wrote:Ours also uses house batteries to start the genset. When we first bought our coach, we also took it for granted that the genset would run....it didn't. It would turn over, but would not run. After some serious diagnosing, I came to the conclusion that the carb was varnished from old gas and the needle valve was stopped up. Run some SeaFoam through thorugh the gas and see if that cleans the carb enough to get it running good. If you have to, disassmble the bowl/needle valve and soak them in straight Seafoam for about an hour and then clean them with a stiff brush before replacing. Onan will tell you that you should replace the carb, but you can take it apart and reassemble successfully.Then run Seafoam in every tank to treat and clean the fuel system from all that crappy gasoline we are forced to buy now. Unless you travel a lot, that's a bunch of gasoline just sitting in a tank going bad if not treated with something.thanks for the tip, I will have to use the chassis battery for now until I make a new battery frame to hold all three batteries. I got it to run somewhat smoother than it was by playing with the adjustment screws, but it needs to be taken apart as you said. I looked at a carb kit which is around 60.00 I think but will try what you said first. Have a new muffler coming so I should be good to use when needed. I hope I can borrow someones tachometer to see if I'm at 1800 rpm too.

When you clean that carb, there are several thing to unscrew on the bottom of the carb, where the main jet goes into the carb, there is a emulsion tube that can be removed with a screw driver, next to the main jet well is the idle jet well, it has a screw driver slot in a cap, unscrew that cap and under it is the idle jet that also unscrews. A inspection mirror is handy unless you remove the carb.

Onan Emerald III 6500 | Good Sam Community

darsben
Explorer II
Jul 20, 2015
Do not know your rig but my southwind starts the genny off the house batteries not the chassis
Deano56
Explorer
Jul 20, 2015
that might be how its supposed to be on mine too, mines too old I think to find any info, thanks
10forty2
Explorer
Jul 20, 2015
Ours also uses house batteries to start the genset. When we first bought our coach, we also took it for granted that the genset would run....it didn't. It would turn over, but would not run. After some serious diagnosing, I came to the conclusion that the carb was varnished from old gas and the needle valve was stopped up. Run some SeaFoam through thorugh the gas and see if that cleans the carb enough to get it running good. If you have to, disassmble the bowl/needle valve and soak them in straight Seafoam for about an hour and then clean them with a stiff brush before replacing. Onan will tell you that you should replace the carb, but you can take it apart and reassemble successfully.

Then run Seafoam in every tank to treat and clean the fuel system from all that crappy gasoline we are forced to buy now. Unless you travel a lot, that's a bunch of gasoline just sitting in a tank going bad if not treated with something.
Deano56
Explorer
Jul 21, 2015
10forty2 wrote:
Ours also uses house batteries to start the genset. When we first bought our coach, we also took it for granted that the genset would run....it didn't. It would turn over, but would not run. After some serious diagnosing, I came to the conclusion that the carb was varnished from old gas and the needle valve was stopped up. Run some SeaFoam through thorugh the gas and see if that cleans the carb enough to get it running good. If you have to, disassmble the bowl/needle valve and soak them in straight Seafoam for about an hour and then clean them with a stiff brush before replacing. Onan will tell you that you should replace the carb, but you can take it apart and reassemble successfully.

Then run Seafoam in every tank to treat and clean the fuel system from all that crappy gasoline we are forced to buy now. Unless you travel a lot, that's a bunch of gasoline just sitting in a tank going bad if not treated with something.
thanks for the tip, I will have to use the chassis battery for now until I make a new battery frame to hold all three batteries. I got it to run somewhat smoother than it was by playing with the adjustment screws, but it needs to be taken apart as you said. I looked at a carb kit which is around 60.00 I think but will try what you said first. Have a new muffler coming so I should be good to use when needed. I hope I can borrow someones tachometer to see if I'm at 1800 rpm too.
jyrostng
Explorer
Jul 22, 2015
When you clean that carb, there are several thing to unscrew on the bottom of the carb, where the main jet goes into the carb, there is a emulsion tube that can be removed with a screw driver, next to the main jet well is the idle jet well, it has a screw driver slot in a cap, unscrew that cap and under it is the idle jet that also unscrews. A inspection mirror is handy unless you remove the carb.
jyrostng
Explorer
Jul 22, 2015
The points gap is important on these too. The points are under a tin rectangular cover on top of the motor with a wire loop holding it on. .015 to .020, I put mine on .020
Deano56
Explorer
Jul 22, 2015
jyrostng wrote:
When you clean that carb, there are several thing to unscrew on the bottom of the carb, where the main jet goes into the carb, there is a emulsion tube that can be removed with a screw driver, next to the main jet well is the idle jet well, it has a screw driver slot in a cap, unscrew that cap and under it is the idle jet that also unscrews. A inspection mirror is handy unless you remove the carb.
I'm going to spend an evening and take the carb off and clean all that I can. I will save these instructions from you
Deano56
Explorer
Jul 22, 2015
jyrostng wrote:
The points gap is important on these too. The points are under a tin rectangular cover on top of the motor with a wire loop holding it on. .015 to .020, I put mine on .020
should I even fiddle with the points seeing that it fires instantly? This engine is a little different than my Massey garden tractor's Onans, they have the B43M engines, only thing that's the same is the block I believe
jyrostng
Explorer
Jul 22, 2015
That's what sets the timing on these units, it closes up after a while and can affect it's power output.
Deano56
Explorer
Jul 23, 2015
jyrostng wrote:
That's what sets the timing on these units, it closes up after a while and can affect it's power output.
yes thats true I have forgotten that

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