Petrol Mower starting problem?

Question

I have a 3.5hp Petrol Lawn mower, which is about 10 years old but still works well - when I can actually start it without causing myself an injury. The starter pull-cord will sometimes snatch back and recoil so hard it almost breaks my wrist. If I am brave enough to perservere, once it does start its OK for a while, but then when I am least expecting it, following a stop to empty, it does it again. I'm almost getting afraid of it now. What is causing this and is there a quick fix, other than a new mower?

Answer 1

Needs a tune-up.(new spark plug,replace air filter,clean carburetor bowl,re-set magneto gap,clean and polish commutator.)

Answer 2

I would suspect the flywheel key first. It indexes the flywheel to the crankshaft. If it is just a little bit off center your mower will exhibit symptoms such as you describe. The remedy is to replace the flywheel key, a simple and inexpensive procedure.
If the flywheel key is not at fault, it will be the valve adjustment is out of specification. This can be more involved and should go to the local repair center.

Answer 3

if its that aggressive on the start and yr timing was of it would not run or it would make alot of popping noise and run rough. if u r not experincing rough running ck under the mower and make sure its clean under the deck, or yr combustion chamber is full of carbon. (the part the spark plug screws in, would have to b taken off and the carbon scraped). P.S yr mower is a newer engine meaning u do not have points.

Answer 4

If it has a breaker point ignition, you should check the point gap. When the point gap is out of adjustment it will effect the ignition timing a bit. You could also check the key between the flywheel and the crankshaft. If it is sheared it will also effect the ignition timing.

Answer 5

Yep, what Amos said. It is backfiring (trying to start in reverse).

Bert

Answer 6

testing...testing