OK, LOOKING TO BUY 99 BOAT WITH 500HPS, MOTORS HAVE AROUND 150 HOURS TOTAL. WHAT KIND OF LIFESPAN CAN I EXPECT. THIS IS A PLEASURE BOAT NOT A RACE BOAT. THANKS IN ADVANCE.

I've had mine for 300hrs with no problems.Engine still performs like new.Just be religious with oil changes & use good syn.oil & good filters.BOB

At about 250 hours the Crane valve springs (usually inners) break. If they are not caught in time, its down hill from there. If replaced before breakage occurs you can go 500 plus hours. Do a search on "valve springs 500HP" on this forum and read about all the carnage.

Ed B