Have a Mercury 500-50 HP,Thunderbolt Ignition,Serial #-2742088,its black with 4 chrome stripes and 2 red stripes around the middle,the removable cover on end is chrome and black that sez-Thunderbolt Ignition,and below that it sez Mercury in white and has red and black trim.Could someone tell me what year this motor is and also what is the compression supossed to be,i checked it cold and it is from 110 to 118,just got it,never put it in the water yet,starts instanly and runs like a dream. Thanks. This is a goooood forum.
