What is wrong with this lawn mower?

Question

My neighbor came over to me the other day wanting me to cut their grass. His wife was cutting grass and she hit a rock. The mower stopped and she figured she broke it. They didn't want to fix it so they gave it to me. So i brought it home and i took the engine off and cleaned the deck and wheels up an it looks good. its only 2 months old. I took the carb off and it is full of oil. The spark plug was covered and oil blows out the muffler when the flywheel gets turned. The piston goes up and down like normal but why is the oil all over? is there a ring that is broken? it is a 5 hp briggs. any other suggestions and ways to fix this?

Answer 1

if there is oil in the carb and coming out of the muffler you most likely blew an oil ring you can get a replacement from some stores or you can look on line for them.

Answer 2

Sugest you take head off and check down the pot. If it stopped suddenly something may have come up through the pistons. Parts for these engines are very cheap just strip it right down. Just because it looks good don't mean nothing. My old lawnmower lasted for 20 years and it was held together with pop rivits , straps and all sorts, but it worked.

Answer 3

Sometimes, oil will get in the carburetor and elsewhere if the mower is tipped on it's side, or even if you are mowing a very steep hillside, (it leaks out through the crankcase breather and into the tube that leads crankcase gases into the carburetor to be burned). I have seen many good mowers junked because somebody thought the rings were shot.

If the person hit a rock with it, there are a couple things you need to check: pull the nut off that secures the flywheel and check to see if the keyway between the flywheel and the crankshaft are lined up, otherwise the key is sheared. Also, remove the sparkplug, hold down any dead-man brake lever, if equipped, and pull the starting rope slowly and evenly and note of there are any "tight spots" (suggests that the crankshaft is bent). If you can get it to run and there is a lot of vibration, the crankshaft is probably bent. It is unlikely that the connecting rod is broken from the mower hitting a rock, that usually happens from running it with no oil.