Small Engines (Lawn Mowers, etc.): B&S 18.5 hp boxer twin engine full of fuel, rideon mower, neddle

Question
Hi Michael

The night before use we filled our MTD rideon mower with fuel...and thought no more. The next morning Sandra tried starting the mower but it wouldn't run. I came home and tried all sorts of things, it fired a couple of times but was very sick. Finally I worked out we had about 3l of gas in the sump!  Also the fuel filter was toast. My deduction was a leaking neddle valve from dirt on the down draft carb. We cleaned it up and put fresh oil in.

Now we have a number of other problems - surging (i'll clean the carb a few more times), and lots of white smoke (even after the mower has run long enough to burn the muffler dry of fuel).

Why would i have so much white smoke? A compression test gave us 110-120psi is that ok? Will the engine need work?

Thankyou, Ralph & Sandra

Answer
Hi Ralph & Sandra,

You were right about the leaking fuel and on track with the other problems.  The surging is most likely due to a weak governor spring.  The white smoke is due to either, some remaining contamination in the oil or oil residue left somewhere, from when the crankcase was over filled with fuel.
I would get the engine running well and run it for a while.  If the smoke doesn't stop, let me know.

Good Luck,
Michael