I am using 87 octane as recommended and its the same that I use in the
lawn tractor. The plug gap is .030", its a NGKBPR6ES as specified. The
engine does not smoke, I will be mowing along and it will seem like
its fuel starved and quit. This happens about every third time I mow.

No I dont add fuel to the gas as its a four stroke engine.

Thanks

if you keep the air filter clean then it might be time to go to sears tech
support while you still have a warrenty