volvo duo prop,reprop?

[ericv26]

he guys. my boat is a 1975 v26 stamas americana with a volvo penta 290 duo prop with 350 chevy engine. engine was rebuilt this winter and I have just finished breaking it in.yesterday I opened it up to wot for the first time. ran 33mph at 4300 rpm in slight to moderate chop. was thinking I should be able to get more rpm out of it. should I consider a reprop or should I just be happy. also what direction do I go on the props? I know that they are numbered so do I go numerically higher or lower? thanks eric

 

[bruceb58]

Re: volvo duo prop,reprop?

4300 sounds about right. Try it again in smooth water and your RPM may actually be higher. The higher the number, the higher the pitch.

 

[Walt T]

Re: volvo duo prop,reprop?

Verify the tach reading they are notoriously inaccurate. Speed is GPS? It's a '75 26 footer? I agree, sounds about right. No harm in verifying basic stuff like ignition timing, point gap, throttle plates opening, choke flap opening, or even compression.

 

[ericv26]

Re: volvo duo prop,reprop?

Thanks guys.I just was checking. I know it is a heavy boat and just want to squeeze all I can out of her

 

[jerryjerry05]

Re: volvo duo prop,reprop?

If? Your trimming like it should be done.
Trim tabs? Up all the way?
Load??
4300's about right.
But if you do change?
The pitch should go down.
Say from a 19 to a 17 on a normal app.
But there are a few guy's over on the prop section that'd be able to give you a better idea on what to change to.
I know the Duo-props aren't cheap$$$$$$