TOPIC: prop selection

Ok a little back ground I have 1968 glastron that weighs 880 lbs with a 1968 merc 125. add that together with 300 lbs of gear and me and I can get it above 4200 rpm and it starts to cough and sputter. up to the 4200 rpm seems to run great. I had a friend with me we tried pumping the fuel bulb incase it is running out of fuel did not seam to help. next thought is where should I start on prop pitch.

4200 IS WAY too low for wot. The standard prop on those from the dealer was a 15 P for heavy boats. I would start there and watch your rpm. You may end up with a 17P.

I am gunna pick up a 17 pitch this weekend and see what it does. It does not feel like its lugging at all. It seems pretty spunky off the line. But i am not an expert by any means. I will report back with my findings.

What prop are you currently using, sounds like 21P. Way too tall.

I agree. That motor should wind out to 5000 to 5500. With the right prop it will snap you right out of the hole. I have a 1959 Thompson in the same weight range with a '77 115 Merc. Mine runs out to about 5200 and I get over 45 mph alone. Your hull is probably made a little more for speed than mine. I am running a 19 pitch. I hope that helps.
Bill

Its a 19 pitch 3 blade. I will try somthing lighter and see what it does. I am getting about 32 by myself.