So, I just recently purchased a 1987 Yamaha pro 50 LH on an '87 alumacraft classic deluxe. The guy I bought it from said it ran good last he had it out, which was last year. He had replaced the impeller, and told me that sometimes he would lose power at a high speed due to the spark plug wires coming lose. Other than that it ran good on the muffs but the impeller/pilot stream looked weak. When i took it out for the maiden voyage , the overheat alarm went off and it bogged down at full throttle. The spark plugs were fouled, the fuel line/tank was shot, and the pilot hole water was steaming. So i changed the spark plugs, zipped tied the spark plug wires onto the spark plugs, bought a new gas tank, gas line and adapters and put in a new impeller including housing and gaskets, and a new thermostat. that all seemed to fix the overheating problem but the bogging down at full throttle persists. I can get going to full throttle for 5 minutes or so(sometimes longer) but then eventually it bogs(never dies) and I throttle back and it runs fine at half throttle and lower. It also is a little chuggy and smoky at start up, which i attribute to being old but maybe another symptom to my problem? I'm thinking about running some seafoam thru it for a couple hours, maybe that'll clear it up? I dont know if the guy i purchased from winterized it. I'm new to the forum, any advice is much appreciated.
