How much oil do you put in your lawnmower?
The question is too vague to give an accurate response, 2 cycle engines like chainsaws & snow mobiles take a 2 cycle oil / fuel mixture that varies anywhere from 8,16,32 etc to 1 however if you do an online search of the motor manufacturer & provide the information that is contained on the silver colored metal tag usually riveted near the carburetor on the rear side of the block they can tell you the exact weight (10w30) & quantity to maximize the engines lifespan
My mum has accidentally put a whole bottle of lawnmower engine oil in the lawnmower and now it won't start what do i do?
If the lawnmower has two compartments one for gas and the other for the oil, then put gas in the gas and a 30w type oil in the oil compartment. Simple as that. If you have an engine with only one compartment then you'll need to check on the manufacturers suggestions which is usually 40:1 or something close.
Depending on the model of the Craftsman lawnmower, there is either an oil plug underneath the deck of the mower which needs removed to drain the oil or the lawnmower needs tipped on it's side to allow the oil to drain out through the oil cap area. Once oil has drained you will want to refill the oil until the dipstick registers "full".