QuestionI have an 18.5 hp b&s intek plus single cylinder engine in
my Craftsman DYT4000 lawn tractor. Engine # is
31P7770348E1. When you first turn it over to start it, it
will crank a couple of times and backfire like a shotgun.
When you try again it may backfire again or it may start.
Once started it will run fine. It does have the anti-
afterfire solenoid on the carb, but my understanding is
this prevents the backfire upon shut down not start up. Any
help is appreciated.
Thank You,
And may God bless,
Kyle
Answer It sounds like you may have a sticky valve that may be sticking open until it gets moving a bit. You might remove the valve cover
and watch while someone cranks and see if one of the valves doesn't
return to the same height, and some good squirts of carb spray may get in there and dissolve the varnish, if not, you may have to pull the head and remove the valves for cleaning. The real danger is that
the valve may stick open too far and the piston hits it and destroys the engine.
Just take a look, if you are careful, the valve cover can be reused, it is worth a look at the top of the valves. Let me know what you find.
