Lynn,

My plugs always have a rounded tip after 15-20 hours.  By then they are mis-firing at idle and I chuck them.  (Actually I have a large drawer full of them from the last 735 hours of operation!)

These are the factory NGK BUR7EQ and 9EQ (cheap).  If I were to try a colder plug, I am stumped on the listings about what to try and which will fit without grinding off those ears on the rotor housing.

Could you steer me to a part number that I could try?  No liability, I promise.

Bill Eslick

13B NA