Onan motor won't start on Champion 16 welder

[sedgehammer]

Bought this unit last early spring

Onan model #1216G-1/11199E

Had some issues, put a new coil on it. Ran fine till about 3 weeks ago. Would start, run a few minutes then quit. Sometimes would start back up and would run fine. Sometimes would have to wait 15-20 minutes and it would start up and run fine

Now it won't start. We replaced the fuel pump with an electric one. The vacuum style wouldn't keep the bowl full. Now we have enough fuel. Did run for 30 seconds earlier today, now nothing again

Thinking the mag is not producing enough power consistently, but not sure

Any idea's out there

[paramax55]

This is going to sound stupid, but did you try changing the spark plug? I had a pressure washer do the same thing. Spark plug looked fine, but I had tried everything else and my shop had a bunch of running engines with proven spark plugs in them. Wouldn't you know... the problem went away with a new plug. A couple years later, a buddy brought me a lawnmower with the same issue - I looked like a genius.

[walker]

There is a fuel line on my on an that goes from the pump to the carb. It has a tight turn and a size change. It cracked and caused me starting problems for a long time.

[Carbon-Arc]

Just the basics:
Air, fuel, spark, and compression.
Are the intake and filter unobstructed?
Is the carb functioning well? (No clogged jets, adequately function float, etc.) Fuel lines, tank, and filter unobstructed?
Are you getting spark? You can test this yourself with a screwdriver (you will be the spark detector in this case) or with a multimeter. Have you inspected the condition of your spark plug?
Compression, if you have a tester, pull your spark plug and crank the engine over 5 times, see what the reading is. If it's too low, add some engine oil to the cylinder. If compression improves after adding oil, your piston-ring-cylinder seal is worn, if it doesn't, it's probably a burnt valve.

[danielplace]

Bought this unit last early spring

Onan model #1216G-1/11199E

Had some issues, put a new coil on it. Ran fine till about 3 weeks ago. Would start, run a few minutes then quit. Sometimes would start back up and would run fine. Sometimes would have to wait 15-20 minutes and it would start up and run fine

Now it won't start. We replaced the fuel pump with an electric one. The vacuum style wouldn't keep the bowl full. Now we have enough fuel. Did run for 30 seconds earlier today, now nothing again

Thinking the mag is not producing enough power consistently, but not sure

Any idea's out there

Sure the plugs didn't get wet maybe carb is not right.

[SweetMK]

How old is the gas?,, Ethanol fuel gets kinda hard to start after a few months,,
and ,, after a year,, it can be down right miserable to start some engines ,, just because of the age of the fuel,,,

[BD1]

Old fuel is always an issue. I add stabil to all my fuel. Sometimes I remove air cleaner and spray ether into carb for an extra kick start.


Sent from my iPhone using Tapatalk

[smithdoor]

I found engines that sitting over may gas tank and carburetor clean.
I drain my tanks and carburetor after each use (less cleaning)

FYI 2 cycle engines just case of spark plugs or a sandblast

Dave

Bought this unit last early spring

Onan model #1216G-1/11199E

Had some issues, put a new coil on it. Ran fine till about 3 weeks ago. Would start, run a few minutes then quit. Sometimes would start back up and would run fine. Sometimes would have to wait 15-20 minutes and it would start up and run fine

Now it won't start. We replaced the fuel pump with an electric one. The vacuum style wouldn't keep the bowl full. Now we have enough fuel. Did run for 30 seconds earlier today, now nothing again

Thinking the mag is not producing enough power consistently, but not sure

Any idea's out there

[SlowBlues]

Seafoam for me.

Seafoam is also a great fuel stabilizer. I typically add a little more than recommended, about 1.5 oz per gallon. instructions on Can recommend 1 oz/cap-full per gallon.

It does wonders for carbed and smaller engines that sit long periods of time.

[sedgehammer]

Thanks everyone for your replies. we were very thorough in checking everything. It was the ignition module. We replaced that and the exciter ring. runs fine now