Too high a pitch?

[JerrfyLube]

Ok, about the boat...

17' Challenger(mini day cruiser style boat)...no idea what it weighs but its fairly light

1971 135HP Mercury

19 Pitch 3 blade bronze prop...looks like it has a slight cup to it and its in overall good shape a couple small nicks aside.

Halfway calm water and playing around with the trim for max speed i was turning approx 4800RPM and hit 45.1 MPH on my GPS. It feels a little slow out of the hole but once its on plane its a throw you back in your seat ride till you hit full throttle. Am i where i should be at prop wise or do i need to go with a little less pitch to get the RPM's up a little bit?

 

[cell]

Re: Too high a pitch?

Seems your wot rpm is low.I think you should be around 5500 or so...

 

[steelespike]

Re: Too high a pitch?

I believe the 135 rpm range is 4,800 to 5300.I you Drop 2 inches.
It should put you at about 5,200. with more hole shot.Top end may tail off a little.I would say your present set up works unless you run with lots of people or need a little more jump for skiing.

 

[JerrfyLube]

Re: Too high a pitch?

I believe the 135 rpm range is 4,800 to 5300.I you Drop 2 inches.
It should put you at about 5,200. with more hole shot.Top end may tail off a little.I would say your present set up works unless you run with lots of people or need a little more jump for skiing.

Sounds like a 19P will work fine then...was hoping to get a little more top end speed out of the motor but in all reality, 45MPH is plenty fast!

I do have a 2blade 17P i might throw on it just to see what it does...

Which imparts another question...the prop thats on there is borderline needing replacement and if it does get replaced, its going to get an aluminum one because for how hard i am on props, im too cheap to be replacing bronze ones often. Will that affect performance at all by just changing prop materials(assuming the same pitch and cup)?

 

[Dhadley]

Re: Too high a pitch?

A typical bronze prop won't have much lift and won't like to run very high. Don't be surprised if a good ss 19 would produce more rpm and speed.

 

[cell]

Re: Too high a pitch?

I believe the 135 rpm range is 4,800 to 5300.I you Drop 2 inches.

Is it?I was going off of what I read in the forums.Tho I read it last year...Maybe Im thinking of a lower hp merc.