2 stroke fuel in 4 stroke engine

[david1095]

Hi all,
Yesterday I stupidly filled my lawnmower tank with two stroke oil and ran it for an hour without any issue. The next day I fired it up and it seemed OK but then stopped via a large enough release through the air intake. Now I am unable to get it started. When I pull the chord it is quite stiff, but when the engine tries to turn over it back fires (again via the air intake) again it seems it won't start. Any suggestions - have I shot the engine?

Thanks, David.

 

[RayMcD]

Little extra oil never hurt anything, r

 

[FL Mower]

Are you saying you put 2-stroke oil in the oil pan of a 4-stroke mower, or that you put oil/fuel mix for a 2-stroke engine in the 4 stroke mower's fuel tank?

 

[david1095]

Are you saying you put 2-stroke oil in the oil pan of a 4-stroke mower, or that you put oil/fuel mix for a 2-stroke engine in the 4 stroke mower's fuel tank?

I put the 2 stroke fuel in the fuel tank of the 4 stroke engine - now its not starting and back firing through the air intake? Have I clogged up the carburettor?

 

[Scrubcadet10]

The fuel shouldn't have caused an issue, some people will run 50:1 or higher ratio in engines that haven't ran in awhile for upper cylinder lube on a first start.
Post the model of the engine, or at least a picture of it so we can see what we're working with.

 

[bertsmobile1]

That is generally the flywheel key broken which causing the timing to be off or a problem with the intake valve not sealing properly .

 

[olgeezershonda]

I’m not sure what might have happened or what “large enough release” means. Fuel?

Something to try. Remove the spark plug and see if it turns over easier. If so maybe it’s flooded badly and partially hydro locked. Watch to see if any fuel spits out of the spark plug hole. While its out ground the plug on the engine block, pull the rope and see if you get spark. Let us know what you find.

 

[david1095]

The fuel shouldn't have caused an issue, some people will run 50:1 or higher ratio in engines that haven't ran in awhile for upper cylinder lube on a first start.
Post the model of the engine, or at least a picture of it so we can see what we're working with.

 

[olgeezershonda]

I glossed over the backfire. What Bert says makes sense.

 

[mmoffitt]

no report?