HI, I change my spark plugs and saw that the plugs that i took out were Champion RV15YC4. I put in Autolite AP 104 which should be the same as the volvo penta plug that the manuel recomends. The autolite plug is about a half inch longer then the champion plugs i took out. Would anyone know if i was doing any harm to the engine by having the wrong plugs in it. It did seem to run fine. I ran the engine all last season with those plugs. thanks
