prop advice

[TMALEGA]

Ok I now have my prop on and fixed to look brand spanking new. So we were out yesterday and while I was out by myself it was running close to if not right at the 5000 mark put everyone in it and we dropped to 4200 around 30 mph with my phones gps. Ok so here are the specs it is a 1974 starcraft america 16 ft v haul, 1985 85 hp force motor. With a 19 pitch al prop on it, Rough weight estimate with everyone in it is maybe 700 lbs in people and 12 gallons of fuel and the 2 batteries. Should I be happy with the way it is right now or should I change to a 17 pitch prop? Or do/ can I go up to a 21? Not real sure which way to go.

 

[steelespike]

Re: prop advice

You might be able to raise the motor on the transom. The antivent plate(just above the prop
should be about even with the bottom to about an inch above.You might gain a mph and a small improvement in hole shot and rpm.
Careful adjustment of trim may help.
Probably easiest and best solution you could go to a 17" pitch it should add 300 to 400 rpm putting it close to the max.
Would help with a load and improve hole shot.
You may be able to repitch the 19 or get new;giving you a spare.

 

[TMALEGA]

Re: prop advice

Ok i cant raise the motor any more on the transom, any higher and the inner mounting screws are going to be off the boat. That plate you are talking about is about the same height as the bottom of the boat. So i will see about the 17 pitch prop, am i wrong or is ok to run the boat at what i have for now and before i am getting on and off the water run it around with just myself so i can get the 5k mark and that would blow out the build up that happened with all the weight in it? Thanks again guys.

 

[steelespike]

Re: prop advice

Sure, your fine at 5,000 Do some tests and enjoy the boat.

 

[TMALEGA]

Re: prop advice

Thanks steel i appreciate it. I will see about getting the 17 so i can get the rpms up while i have the family in the boat. I only get the 5k mark when i am alone. Around 4200 with them all in it, but i only got to do about a half hour of testing since the ground wire on my tilt/trim motor broke on me half way through the test

 

[Mac525]

Re: prop advice

I looked up the specs for your motor and wot is 5500rpm with you may still not reach with the 17 pitch. What diamiter is your current prop you might be better off with a 16p four blade or a 17p with a slightly less diamater

 

[TMALEGA]

Re: prop advice

Its a 13.25 x 19 i am under the impression with this motor you cant really do much since there arent that many props available. I am not sure what i can do i found some sediment in the fuel filter bowl this afternoon. So i am going to retry again soon i hope, looks like more storms this week so i may have to put it off for a few days. I had a different problem that developed on the way back to the dock a lack of power. I was working on that most of today and found a nice size peice of something in there. Might change something along with the tilt working again. Wonder if i can get the extra prop i have changed to a better pitch for my boat. Thanks for the advice.

 

[Mac525]

Re: prop advice

A good prop shop should be able to fix you up and they might have a couple you can try to see what works

 

[TMALEGA]

Re: prop advice

So i got in touch with my prop shop who did the repair and sold me my back up prop they are going to take my back up or repaired one and repitch it for me in order to get me to a 17 degree and he said hope fully no charge, un less it needs some welding or something. It is as far as they can repitch it but he said it should make a difference, also they dont have a 4 blade prop for this motor. He said he can modify my lower and get me different props but i would rather not mess with that and get the 17 and be good for the season. Thanks for the advice.

 

[Mac525]

Re: prop advice

I was just looking online and I think pro pulse makes an adjustable four blade composite any where from 11p to 17p all in one prop I have one on a 75 hp evinrude and I really like it.