older mercury 150 bogs at wot

bigdawggie

Seaman
Joined
Jan 12, 2008
Messages
51
Hello,

Newbie here so bear with me please. I have a 71 kona with a 150hp mercury It is most likely a late 70's early 80's motor (the prop guy says xr4 because of the small gear?). Last summer i took it out and it ran awesome with a 17" prop. I bought a new 21" prop and took it out and ran ok for the first trip down the lake but on the way back I was running at WOT and after about 30 seconds the motor lost about half of its power but did not stall. I let off on the throttlefor about 30 seconds then went back to WOT worked fine for about 30 seconds then the same problem. Any ideas what it could be. I think it is fuel related but since the only change since last summer is the prop i thought i would throw that in. I dont have a water seperator and i haven't replaced my fuel filter yet will do that this week.

Thanks for your help
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: older mercury 150 bogs at wot

Big, Have someone pump the primer bulb at WOT. If the speed is maintained, you have found that you have a weak fuel pump. They are easily rebuilt.
 
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