i took all advise and really had to push to get the cap on the dl 50. since everyone thinks the stock plug is guano, and since i felt that removing the cap would make it easier to fall off after removal a few times, i got the ngk plug, hoping not to have to change it for many moons. have a 40 yr old chainsaw that i just this year changed the plug... keep a good oil/gas mix and the plugs dont foul... thanks guys