prop advice

[capped]

Hey all, i'm just looking for some advice. I have a 2002 14 ft fisher avenger side console model with a 2003 mercury 25 hp 2-stroke. I'm currently getting about 4300 rmp at WOT which is considerably lower then the 5-6000 which the motor is supposed to run at. I have a top speed at 23 mph gps which seems to be pretty close to what a 25 hp can do on most boats this size. The stock prop is still on it and it is 10 1/4 x 13p. Is it normal for boats to be this overpropped from factory or is maybe my tach not reading right? At idle i get about 800 rpm on the tach which seems to match up pretty well. Thanks for any advice.

 

[steelespike]

Re: prop advice

I think the 13 may be a little too much prop,but::I think the 25 is rated at
about 32 on a light utility type bpat.
Before making a prop change you might try raising the motor.The antivent(cavitation)plate just above the prop even with the bottom is considered a starting point.Raise it to a point just before venting becomes a problem.Be sure it pumps water.
This could net a little speed and some rpm.Then before making a prop change
Check out the Turning point Rascal.An 11 may be the ticket.

 

[capped]

Re: prop advice

Thanks for the response. I think i have five holes where i can adjust the heighth. Right now i'm in the second one away from the transom, so maybe if i move it out a hole or two it will give more rpm and speed. That is what you are saying right?

 

[Irv964]

Re: prop advice

Thanks for the response. I think i have five holes where i can adjust the heighth. Right now i'm in the second one away from the transom, so maybe if i move it out a hole or two it will give more rpm and speed. That is what you are saying right?

Second one away from the transom?? And move it out a hole?? Please explain?
Steelspike is talking about raising the motor height up, not out. Your cav plate(large plate on motor) should be even with the bottom of the boat(starting point) if it is below right now, this is what he is telling you to do, raise it until it as at least even/level with the bottom of the boat(fully trimmed in) and raise it from there after you test each new height ensuring you still have good water pressure and venting isn't a problem. Hope this helps explain it better if you didn't understand Steelspike?.........Irv964