Motor Fouling Problem

I've got a 1998 P.T. 175 with a 40 hp force/mercury. The motor has two cyclinders and the top (gapless) sparkplug always seems to foul very easily causing the motor to miss frequently. I've tried running "powertune" throught the motor and that fixes the problem along with a new set of NGK plugs for a few hours of running time, but the the problem is back. ANY IDEAS WHATS WRONG? I'm getting ready to park this boat in the dealers parking lot and tell them to fix it. But, when I ask them what to do about this problem, they tell me to just keep a few extra plugs onboard. One thing; the motor turns over everytime with just a touch of the key (thanks to my Optioma batteries). PLEASE HELP.

may have your ignition checked could be a weak fire problem to that cylender.coil aor wire could be breaking down under a load,coils are hard to check,it will fire strong when its cold but fall off when the heat builds up.i have switched the coils with other cylenders to see if the problem follows that coil if not take it to a dealer who has the equipment to test it.probably be a power pack

what do u mean by gapless plugs? if your using the new center fire plugs that may be the problem, i tryed to put them in my motor but the dealership said they would foul out to quickley in my 70hp. just a though. happy huntin

What plugs are you using? My Motor calls for Champion L76V or NGK's BUHW.