Onan engine

leva

Member

Engine started backfiring after warmup and at nearly full throttle. Is this a sign of running lean or possibly a bad fuel filter. Anyone have any suggestions. Thanks for your help.
 
Billy it is an Onan 16 hp. Model B43 in aCase tractor. I just wonder if I may have gotten some bad gasoline because it starts excellent as always.. thanks foyour help.
 
I would like to have full modelserial number.That engine had some small changes.

But I will cover the basic engine.
Could very well be bad fuel.You might try running it on. What you know to be good clean fuel. From a clean gas can.
Could be from clogged fuel filter.
Check the point gap. Should be at
B43E 0.016
B43M 0.021
Does it have plenty of oil.
If it has Champion Spark plugs. I would switch to another brand. I had 5 fail in one week.

If you want a manual. Go to Onan Manuals. Click on
INDEX OF/
You will find
965-0757 for the E model
965-0754 for the M model
Manuals are free.
 
-Valve adjustment
-Broken valve spring
-Intake leak
-Plugged up carb
-Points, condenser, timing
-Collapsed or pinched fuel line
-Plugged fuel tank vent
-Loose electrical connection
 
(quoted from post at 06:12:16 09/26/20) -Valve adjustment
-Broken valve spring
-Intake leak
-Plugged up carb
-Points, condenser, timing
-Collapsed or pinched fuel line
-Plugged fuel tank vent
-Loose electrical connection

Good list!

Also:

-Valve seat loose in block
 

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