"Unni" wrote in message
oups.com...
I have a Craftsman Lawn tractor that needs to be jump started to get
going but used to run fine once it started. It will restart on its own
once it runs continuously for 10-15 minutes.

As of today, it shuts off if the jumper cable is removed. Could it be
alternator? the battery (possible shorted cells)? os something else?


The choke is probably not functioning.

All cold engines need a super rich mixture to start. Cheap engines use
prime bulbs that you push in a half dozen times, this pumps raw gas
up and squirts it into the fuel intake tube from the carburetor. Better
engines use an automatic choke flap that engages when the engine is
cold then a bimetallic strip opens it when the engine is warm. When
you start these the priming is done automatically by the choke.

Something is messing up this system. If the engine isn't run regularly
the carburetor passages are probably clogged up with varnish from
old gas. If it is a carb system (which I'm sure it probably is) then
sometimes pouring out half of the fuel then replacing it with
Berrymans' B12 Chemtool and running the engine a bit then letting
it sit for a while will melt away the varnish in these passages. Otherwise
the carb needs to be disassembled and cleaned.

Ted