150 Mariner no power to get on plane.

DocBob

Petty Officer 2nd Class
Joined
May 15, 2002
Messages
129
I moved from sea level to about 6000ft. I changed out my jets (no adjustment screws on these carbs) according to the Merc specs, and had a mechanic give the engine a once over, check compresion, linkages, and change timing. He said the only other thing I really needed to do was go down 2 or 3 pitches in my prop. So I replaced my 3-blade stainless 24 pitch prop with a 3-blade stainless 21 pitch prop. Well long story short, I can kill the engine trying to get on plane without much trouble. If I have my friend walk up to the front of the boat we can usually get on plane, but not when we're both seated. The boat is only a 17ft fiberglass bassboat so nothing big. Is it possible it just needs an even lower pitched prop, or does it sound like it needs more work. Once on plane it'll do 55+mph and starts great. It seems to be running fine just not enough power to get up and go. The motor is actually the max the boat is even rated for so it cetainly shouldn't be underpowered.<br />Any suggestions would be greatly appreciated.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,073
Re: 150 Mariner no power to get on plane.

Bob, A lower pitched prop will certainly help get you up on plane easier. I would also examine the plugs for the correct color, so you know your not too lean. I would think you will want a prop that will plane the boat with 4-5 occupants. It sounds like 17-19 pitch is that number.
 

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
Re: 150 Mariner no power to get on plane.

Also, we need to know what the WOT RPM is when you are flat out. You are on the right track though!
 

DocBob

Petty Officer 2nd Class
Joined
May 15, 2002
Messages
129
Re: 150 Mariner no power to get on plane.

Thanks for the input. I knew someone was going to ask the WOT RPM question, and I'm not sure right now. Unfortunately I thought about that as I was pulling the trailer out of the lake this weekend. I'll have to get back to you on that. In the mean time I'm going to try to find a demo prop and try that as well. <br />Is there a rule of thumb on re-pitching props for altitude? My 24p worked pretty well at 0ft. above sea level. It sounds like I possibly should have gone down 5 to 7" in pitch to run at 6000ft? My other lake is at 8000ft. It looks like I might need a couple of props around here.
 
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