1989 Yamaha Pro50 cylinder out?

AtlanticPanic

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Jun 30, 2002
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Just put boat back in water... runs fine day 1, but on the way home, konks out down to 2400rpm for last few miles of trip. day 2 runs fine after I replaced #3 (bottom) plug. put on new fuel tank, and added 89 octane at end of day (usually use 93). day 3, get out 1.5 miles, just past no wake 5mph zone, then open it up, go 1/4 mile, and boom, back to 2400rpm again for rest of day, even after replacing all 3 plugs w/new at marina. day 4, runs fine for 2.5-3 miles, then down to 2400rpm again. anchor, change back to old tank and fill w/93 octane, then runs fine for rest of day, but a bit rough at mid rpms. day 5, head out, get 2.5 miles w/out incident, run fuel down in case of bad gas. fill w/ new 93 octane fuel, take off for 1/4 mile, bango, drops to 2400rpm again for remainder of day. also, seems to leak some slick, could be fuel, but may be hydraulic oil from trim/tilt pistons. who can tell me what is up? fouled plug? bad wire? coil? ideas???? I am DYING for help, I cannot get a mechanic for weeks on Cape Cod and I need to fix for July 4th and commercial striper season... Thanks in advance! -Stephen
 
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