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Wayne, Engine Rebuilder
Category: Small Engine
Satisfied Customers: 9446
Experience:  many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines
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I have an Onan E140H engine that ran like a top last time I

Customer Question

I have an Onan E140H engine that ran like a top last time I used it which was 1 week ago. I tried to start it this week and it just backfires through carb. I checked and have good spark. Replaced all gas lines, cleaned carb. I added a fuel additive to gas, it started and sounded good. Took it out of garage turned on mower deck, shut off like it didn't have enough power to run it. It restarted and tried it again with same result, now it is back to just backfiring and won't start at all. Hope you can help.
JA: Do you have fuel in the tank? If so, is the shut-off valve open and the fuel clean?
Customer: No shut off on tank, I had cleaned tank replaced fuel lines, and replaced fuel.
JA: Do you plan on doing the work yourself?
Customer: I have a good friend that repairs mowers and doesn't want to help on this engine. But he has been telling me what to do. I have rebuilt diesel motors for years but this is all new for me but I will try.
JA: Anything else we should know to help you best?
Customer: I have not check timing yet.
Submitted: 9 months ago.
Category: Small Engine
Expert:  Wayne replied 9 months ago.

Hi I'm Wayne

I will help you with this

What you are describing is plugged jet in the carb

remove the carb, disassemble , boil out in a pot of hot water 10-15 min

air dry, and put a rebuild kit in it

I hope this helped you

Hi. If this helped you,

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Expert:  Wayne replied 9 months ago.


Just a follow up with you

did my answer help you

let me know, Please


Customer: replied 9 months ago.
The problem was the spark plug
Expert:  Wayne replied 9 months ago.


That is strange that it ran

But glad it is going for you