Bringing up an Old Topic. Mercury 150 Black Max

[powderhoundbrr]

Well I am back at it again trying to get my Mercury Black Max 150 up and running. It is on an open bow Maxum 18 foot. I just went through the motor, corrected the timing, got a carb re-build kit , got that going and the motor is running great until it under load. I get can get an immediate 5600 rpm without a load on it.

Currently running a17 pitch prop and I can only get 2900 rpm out of it, if I give it 500 meters I can get it up to 3500 and the hole shot is non-existent. I have been trying to get this thing running for 4 years on and off now and after a few tests runs yesterday I am still at square one. wondering if a 13 pitch prop might be the way to go or if anyone has any suggestions. I was all over this forum years ago but I kind of gave up on this boat but I guess I am going to try again.

 

[Leardriver]

Compression test equal-ish across all cylinders? Fuel is my next stop. Carbs clean and flowing, or gummed up from sitting?

 

[powderhoundbrr]

Yep compression pretty equal on all of cylinders (within 10 psi anyway). Carbs have been cleaned and are working well. I had a mechanic go through it with me. And he says there is no reason this thing should not be running like a top.

 

[Chris1956]

Did you check the high speed stator winding?

BTW - I would think a 17P prop would work better than what you report.