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4500 rpms is all itbll top out

robalo_82

New member
"i bought this boat without a

"i bought this boat without a water test the owner said it was in great shape and it sounded great on the earmuff my problem 1994 150 hp yamaha will only top out 4500 rpms at about 3/4 throttle then no more increase at full throttle had a 15x17 prop only top out about 4800 them i changed to a 15x15 prop only get 4500 rpms i can trim out raises it to 4800 but bows bounces to much. the carburetor linkage appears to full open at full throttle has anyone every hear of this problem....my specs. stated rpms should range between 4500-5500, but prop guy said it should be closer to 5500 rpms. might add spark plug are correct with right gap but were black and oily after only 3 lake trips and a half dozen earmuff flushing, compression on all cylinders 117, 116, 117, 118, 117,119 with no leakdown...someone clue me in before i go to the yamaha dealer...thanks"
 
"You may need the carbs cleane

"You may need the carbs cleaned / serviced or even have a tired ignition system , if it's a weak ignition you could try the NGK iridium plugs( stronger spark ) but you should still have it checked by a mech."
 
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