Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

[tblack111]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

Only thing is, I would have to go to a 3 blade prop to get down to an 8 pitch in a stainless for this boat. Any thoughts?

 

[steelespike]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

An 8 inch 3 blade should have plenty of hole shot and load ability.
And even should do better than a higher pitch staying on plane with less throttle.
Have we talked about raising the motor to a point just before venting becomes a problem?
Might not do much but could add a couple hundred rpm and some speed.
A ss will usually allow more height and of course the 4 blade as well should do well.
a 2" increase could give a noticeable improvement.

 

[Mi duckdown]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

Gotta ask. is the boat set up a tiller or console steering?

 

[tblack111]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

console, doing pretty good now, still a little vibration, speed is up, better whole shot, still may not be all the way on plane . Dont know if its worth the hassle to swap out for the 3 blade 8" stainless. Im about tires of dealing with it...just be satisfies with what I have already accomplished kinda attitude. this is getting expensive. If I could get and inch of pitch dropped in this 4 blade...that may be the ticket.

 

[Mi duckdown]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

tblack111. and this my take on this. There is now way, you are going to get good performance, with a console 17 ft, with a 25 hp.
I looked up the specs on that boat. way under powered.
Just My .02

 

[John_S]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

Agree that it is underpowered. But, you are doing ok for the weight of that rig, though.

Try a 8"P alum prop. IMO, SS is a waist on small motors, and increases the chance of damage to the gear drive on impact. Lots of $ for maybe 1 mph.

A 4 blade should have less vibration. ???

 

[steelespike]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

console, doing pretty good now, still a little vibration, speed is up, better whole shot, still may not be all the way on plane . Dont know if its worth the hassle to swap out for the 3 blade 8" stainless. Im about tires of dealing with it...just be satisfies with what I have already accomplished kinda attitude. this is getting expensive. If I could get and inch of pitch dropped in this 4 blade...that may be the ticket.

If your getting 21-22 your on plane,but the 25 on a light reasonable fast boat would be good for over 30.Why not see what a prop shop thinks about dropping the pitch a little.
Obviously your not going to see 30 but perhaps we have it so it will still plane with a medium load.

 

[tblack111]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

Solas said that the prop may have been dropped during shipping and it may be out of balance. Also recommended me to take it to a prop ship and have the pitch lowered to 7. Said that should get me where I need to be to get the best performance out of the prop and engine. Prop guy said he would balance it too....so instead of sending it to solas...I'll take it to the prop shop. He said I would have it back by this coming tuesday.

 

[tblack111]

Re: Is there a better prop available for 25hp Mercury 4stroke EFI ? Need advice

Was able to get the prop lowered to 7.5 pitch and a little change in the cup. I get 5300 - 5400 rpms by myself. Add a man to the boat and I get around 4800 -5000... Jerks you back from 2000-4000 rpms and gets ther in a hurry. Slow to get from the 4000 to 5000 +. I guess that thats gonna be the nature of the 25 hp motor. Just under powered for two folks I guess. I dont know what else to try. Still get some vibration too and the prop is balanced. Just wonder if I should have stayed with an alluminum and went to 4 blade or maybe stainless 3 blade???? To expensive to keep trying. Any advice?