should i change my prop ?if so to what ?

[Swordsman]

hello
i own a boat with a 115hp 2006 mercury 4-strokes outboard on a 2.70mX6.95m which is made of wood and fiberglass so it kinda fat
the thing i recently started wakeboarding so i need to know if i have to "tweak" it a bit
even when not wakeboarding when i push down the throttle , it always starts off slow, it is only when i reach about 4-5 rpm it will start gaining speed, im not sure whats the fastest she goes cause i dont have a speedometer
but according to my GPS and it says about 25-30 mph at maximum
obviously and pulling a skier on the back it will go slower
is it enough for wakeboarding ? if not , will changing the prop to a different size make a difference ?
btw i dont know what size of prop i have on it now, i will check it the next time il be on the boat

 

[steelespike]

Re: should i change my prop ?if so to what ?

Is that about 9' X 21 feet? We need more info read"read this first" at the top of the prop forum. Get us as much info as possible.
Your motor needs to be propped so it operates within its rated rpm range.
We need you to tell us the prop size, wot rpm and speed.If you need a tach something like a Tinytach will work.
Gps is excellent for speed.
Your prop size may be near the base of the blades or under the prop nut.

 

[Swordsman]

Re: should i change my prop ?if so to what ?

ok, so il check my prop size and get back to you
what else ? the speed i already told you, il recheck it anyway, and the rpm, how do i get this info ?

 

[Bob_VT]

Re: should i change my prop ?if so to what ?

Just this http://forums.iboats.com/showthread.php?t=287818

 

[Swordsman]

Re: should i change my prop ?if so to what ?

ok, not sure about no 4 tho, how do i know whats my engine max rpm ?

 

[steelespike]

Re: should i change my prop ?if so to what ?

Rpm should be in your manual sometimes you can find it in test reports on the net.
According to my info the gear ratio is 2.07 and the rpm range is 5000-6000.
Your wide open throttle rpm and speed will come from a test run.
When propped right wot rpm will be close to the 6000.

 

[Swordsman]

Re: should i change my prop ?if so to what ?

ok, im not sure if that tells you anything, but i have a rpm gauge on the boat and if i push it all the way down it reaches 6000 rpm

 

[steelespike]

Re: should i change my prop ?if so to what ?

Really can't tell much without the prop size. (near the base of the blades or under the prop nut).
as far as reaching rpm it appears to be right but at 30 mph it must be a small pitch.

 

[Swordsman]

Re: should i change my prop ?if so to what ?

ok il get back to you with the numbers

 

[Swordsman]

Re: should i change my prop ?if so to what ?

ok so i checked the prop it had some numbers and letters on it right between the blades on the side
it says
4877340A4513P

i guess its this one ?
http://greatlakesskipper.com/produc...itch-rh-aluminum-boat-propeller-whub-kit.html