Okay, here is what I have:<br /><br />1996 Bayliner 2655<br />5.7 Merccarb (2brl)<br />Thunderbolt V Ignition<br />No Knock Sensor<br /><br />My Problem:<br /><br />Engine starts fine first time. Warms up normally, oil pressure and all indications normal. After about 15-20 minutes the engine...