Originally Posted by Bob F

wilson1973 wrote:
I have accidentally added petrol to the oil tank of a petrol mower I
could not find and opening underneath the tank and so tipped it upside
down to drain the oil tank ,and then added fresh oil it did work for a
little while but now doesn't want to start or it does now and again
only for about for 30 seconds and then stops with a fair degree of
smoke,could anyone offer me any advice I did have a look at the spark
plug and it looked to be quite oily I don't know if this is supposed
to be like that,maybe tipping the mower upside down helped oil to
spread to other parts of the mower unintended

Take out the plug and clean it. Clean the air cleaner. Crank the engine a bunch
with the plug out, then reassemble and try again. Try to keep it running until
the smoke quits. Tipping the mower can cause oil to leak out through the intake.
You've got to burn that off.