Small Engines (Lawn Mowers, etc.): craftsman lawnmower, starter cord, check oil

Question
QUESTION: dear, Eric

my father has a lawnmower:
craftsman 7.0 ohv
21" hi tunnel mulcher
front gear drive
variable speed
model: 917.3178941
ser# 031904m  026851

Briggs %26 straton engine
engine family: ybsxs.1901ve      275078

so this is my fathers lawnmower and my little brother over filled the engine oil and he cranked it on and it smoked and he ran it like that and know it wont crank on. someone told me it lost pressure and that the engine is bad?
can it and is it repairable and how and what do i replace?or do i need to replace the engine?

thank you, Eric

ANSWER: First thing to do is remove the spark plug and see if you can turn the engine over by pulling the starter cord.  NOTE:  Oil may squirt out of the spark plug hole.

If the engine spins then drain excess oil from the engine.  Check oil for correct level.  Clean the oil from the cylinder by spraying carb cleaner in the cylinder and pulling the starter cord several time to "wash" out the cylinder.  Repeat this step 3-4 times.

When the cylinder is "washed" reinstall the spark plug and see if it will start.  It will smoke if it starts, just make sure the oil level is correct.

Let me know is the mower starts.

Eric

---------- FOLLOW-UP ----------

QUESTION: dear Eric,


thank you, thank you so much!! we did what you told us to do and it started up. i also had to take the air filter off because it got wet . i guess it got wet when i sprayed too much in the cylinder. but when it idles it i guess the word would be nocks  a litte ? and before we cranked it did spin freely. the spark plug is new and the oil new and leveled.

thank you,
Eric

Answer
There is a remote chance the valves may need adjusting or there may be some minor internal engine damage.

Valve can be checke following directions at the link below:

http://www.briggsandstratton.com/engines/support/frequently-asked-questions/answ

If there is some minor internal damage I would not worry about it too much as it is too expensive to rebuild engines these days...cheaper to replace.

Just keep a close eye on the oil level and use the mower as you normally would.  The knock may go away but if it continues to get louder this may be a key something is wrong.

Let me know if you need anything else.
Eric