40 yamaha 4stroke power loss

minnedosa

Recruit
Joined
Aug 4, 2009
Messages
4
My last thread was poorly worded so I'll try again. My F40TLRX is a 1999 model and has only been used a couple of times a year. When I took it out last time, it seemed to take much longer to reach top rpms (around 5400). When it finally did, it ran for a few minites then suddenly it lost power to about trolling speed. After running it at low speed for a few minutes,I gave it full throttle again and it took a long time to reach top rpms then it lost power again as before. I did this several times with the same results. Does this sound familiar to anyone? Any suggestions would be welcome as I cannot afford the marine mechanics rates.
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: 40 yamaha 4stroke power loss

sounds like a fuel delivery issue. start at fuel pick-up in tank, check hoses, connections, primer bulb, quick disconnect on motor, fuel filter, fuel pump, if old degraded fuel was in tank,drain and refill with fresh fuel, then your carbs may need cleaning. drain fuel from carbs to see what's in them..use a clean white rag to drain them on. if carbs need cleaning, you may be able to do it or the Yamaha shop can do it for approx. $125. install fuel/water seperator and use Stabil Marine all the time.
Good Luck!
 
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