Small engine mechanic alert!?

[DanielB]

I have an old Onan generator that came out of a 76 motorhome.
It is one of these generators that has a coil and solenoid switch and all.

Got it to run and everything is fine. Start it up every week or so and let it run, just for fun.

So I have this small trailer that I want to keep the generator on and when I'm putting this heavy beast on the trailer, the generator leans over to the side.. it doesn't fall, just leans over. This might not matter.

Now it wont start. I removed the fuel line and it is pumping gas into the carb. I pulled the plug and it is sparking.

It is not even firing now. What else could be wrong?

[Fyrzowt]

As you probably know, it needs three things, at the proper times.
Compression, spark, fuel. Too little, or too much fuel and it will not start.
Could it be that the spark plug was "fouled" by oil during tipping over?
Spark plug insulater (porcelain) cracked?

[DanielB]

So I did remove the plug and reconnected the coil wire and turned it over, and the plug does spark when the motor turns over.

Mabye not enough spark?
Could be flooded really bad maybe? But I did leave it sit for a few days and tried it again. Same results.. lack of results.

[AirsDream]

Sounds to me like you need Roger (mikethefixit) ... pm him so he sees this and I bet he can help!

[wasagachris]

Daniel try this forum to find your answers.

Antique Engines Antique Tractors Steam Engines and Old Iron

[r carl]

It could have flooded, put in a new plug and try to start, if it dont start pull the plug and look to see if its wet.

[boatdoc]

Originally Posted by DanielB

So I did remove the plug and reconnected the coil wire and turned it over, and the plug does spark when the motor turns over.

Mabye not enough spark?
Could be flooded really bad maybe? But I did leave it sit for a few days and tried it again. Same results.. lack of results.

Hey Daniel;
In order to test for sufficient spark in atmosphere you need to increase the recommended plug gap X [times] 14.7. For instance a 0.030" plug gap will require aprox. 3/8" gap in atmosphere to equal the load under average compression. Secondly, when you tip over 4 stroke engine the cylinder may flood with crankcase oil making it hard to start. Remove the spark plug, drain carb and turn fuel on. Crank the engine with coil wire grounded to clear the cylinder. Install clean and dry plug and crank it. Thanks, "Boatdoc"

[DanielB]

Great information. Thank you, Sir.

[Hoghide]

I had a garden tractor with an Onan engine about 30 years ago, this would make it about the age of your engine. It got so it would start but die immediatly. It had a molded plastic float. I weighed the float, shaved a little of the sides thinking it was binding on the sides of the float chamber, adjusted the float height, and everything else you can think of but the result was the same-no improvement. I began to suspect that the introduction of ethanol to the gasoline had somhow affected the float, so I called Onan customer Service. Sure enough, they confirmed my suspecion and told me they had a new high tech fix, brass floats. I installed the brass floats and no more problem.

[DanielB]

Good to know. When I got my chainsaw they said to use high test gasoline to burn off the water in the ethanol.

[slowmover]

My local shop always recommends mid-grade gasoline. And the carb rebuild (new floats) is an excellent suggestion. ONANs of that era might be cantankerous, but are otherwise bullet-proof. Take your time and enjoy (I've found any number of service manuals & bulletins online on other engines). And the Antique Tractor guys have a great site.

[Naper]

The engine has to sit flat for the float in the carb to properly meter the gas.

[drag'nwagon]

The "lean" has me wondering if the oil level is below the safety switch. Most generators have a low oil shut off switch. Depending on which way it is leaning, the oil level may be below the switch in the oil pan.