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2 stroke fuel in 4 stroke engine

#1

david1095

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.


#2

R

RayMcD

Little extra oil never hurt anything, r


#3

F

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?


#4

david1095

david1095

FL Mower said:
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?
Click to expand...
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?


#5

Scrubcadet10

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.


#6

B

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 .


#7

O

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.


#8

david1095

david1095

Scrubcadet10 said:
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.
Click to expand...


#9

O

olgeezershonda

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


#10

M

mmoffitt

no report?


#11

J

Joed756

If you put straight 2-stroke oil into your fuel tank, rather than a gas/oil mix, you have significantly increased the flash point of your fuel. I hope by now you've drained the tank and replaced it with straight gasoline. This won't hurt anything but the spark plug which will have enough oil on it to impede the spark. None of this, however, explains the backfire.


#12

Beamster

Beamster

There is really not much oil in there; certainly much less than a hand me down Ford Fairlaine that my girl friend's father burdened me with in high school passed through worn rings. I had to put plug seat extenders to get the spark plugs out of the combustion chambers where all the oil was, and yet it started every time.

For quick reassurance, check plug the sparkplug and see if it shows any signs of fouling, but my guess would be not.


#13

4getgto

4getgto

mmoffitt said:
no report?
Click to expand...
I think some people call the fire department before they see if there's any smoke..


#14

M

mmoffitt

official report


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