QuestionI recently had to replace the magneto on the above engine in
a Craftsman 42" riding mower. Also rebuilt the fuel pump
with appropriate kit. After this repair the mower started
right up and ran flawlessly but, only for about 40 minutes
or so. It then looses power and will eventually die out.
Waiting for 10-20 minutes it will start right back up again
and run for a shorter period of time. It appears to have a
spark right after it dies (although it is yellow/white in
color). The compression on one cylinder cold was 100 the
other cold was 75. After it died compression on the first
cylinder is 105 and the second 100. I have not changed the
spark plugs yet but, never heard of them failing due to
heat. The cooling fins all around the engine have been
inspected and are clean of debris. While the engine is
running there is a lot of air flow felt near the bottom of
the engine "cooling chutes". The engine is under load
(cutting grass) when this event occurs/removing the load of
the mowing deck usually allows the engine to run long enough
to get it back to the shed to work on it but, ultimately it
will die out. Thank you in advance for any help/guidance you
can give. Cutting the grass has become a very frustrating
event at our home :( Thanks again, Bill
AnswerHi Bill
You didn't say if you have changed the fuel filter or checked the gas tank for debris that could partially block fuel flow. check these. Also, when you changed the magneto did you make sure there wasn't rust covering the magnet on the flywheel? And, try new plugs. They can go bad if the insulator is breaking down due to heat. Hope this helps.
