prop selection

[thephoenix]

I have a 16.5" bass boat with a 115hp late 60's early 70's vintage "tower of power" I-6 and was wondering if you all could help. Current prop is a 14x21 ss mercury 3 blade. It gets out of the hole fine and runs out to 45mph at 5100rpm. I would like more top end, is there anything I can do?

 

[sschefer]

Re: prop selection

I have a 16.5" bass boat with a 115hp late 60's early 70's vintage "tower of power" I-6 and was wondering if you all could help. Current prop is a 14x21 ss mercury 3 blade. It gets out of the hole fine and runs out to 45mph at 5100rpm. I would like more top end, is there anything I can do?

Double check, but I think the top rpm for that engine is 4800-5200. If that is correct you are running sweet right now.

 

[Dhadley]

Re: prop selection

You're running pretty good now but could use a few more top rpm. If I were doing it I'd start with the set up. Perhaps raise the motor, look at jackplate options if you don't have one etc.

 

[thephoenix]

Re: prop selection

Thanks guys, As for jackplate options it seems that I don't need one. The motor is set pretty high as it is, the cav plate is about 2 inches higher than the flat part of the notch at the stern of the boat. It is actually high enough that in choppy water I have aeration problems even with the trim all the way down. Any other ideas? Would an engine spacer help to get the motor into "cleaner water"?