Need some prop advice!?

[jaxbchangler]

Hey everyone i just bought this jon boat for $500 its a 14.4 sea nymph powered by a 2003 yamaha 9.9 high thrust 4 stroke. My question is what size prop should i use for more top end because right now i feel like the prop i have is too small (its a 8 pitch). The boat is pretty heavy the guy put all wood floors and the casting deck has a stainless steel frame. When im out on the water and give it full throttle its starts moving pretty good then it just starts feeling like too much throttle/power for the prop if that makes since? The motor runs great no problem what so ever with the motor. Any advice would be greatly appreciated! MY HUB IS NOT SPUN!

 

[pootnic]

Re: Need some prop advice!?

Trying to figure out what your "meaning"...
Does the outboard sound like it's bogging down or reving to high?
Without a tach it's kinda hard to get the perfect prop for a boat/motor combo.

I don't own a 4 stroke 9.9hp but do have a old 9.9hp 2 stroke,on a lighter 14' aluminum.
No tach on that outboard but it seems to run fine with a 10 pitch,or atleast it has for 20+ years...

 

[jaxbchangler]

Re: Need some prop advice!?

Trying to figure out what your "meaning"...
Does the outboard sound like it's bogging down or reving to high?
Without a tach it's kinda hard to get the perfect prop for a boat/motor combo.

I don't own a 4 stroke 9.9hp but do have a old 9.9hp 2 stroke,on a lighter 14' aluminum.
No tach on that outboard but it seems to run fine with a 10 pitch,or atleast it has for 20+ years...

its revving too high! almost sounds like the prop wont catch at WOT

 

[steelespike]

Re: Need some prop advice!?

The high thrust has a 2.92 gear ratio, I'm pretty sure your running into the rev limiter.
With nothing to go on I think a 10" pitch is a good starting point.

 

[jaxbchangler]

Re: Need some prop advice!?

The high thrust has a 2.92 gear ratio, I'm pretty sure your running into the rev limiter.
With nothing to go on I think a 10" pitch is a good starting point.

before i saw your reply i ended up getting a prop with 9'' pitch from this site and should receive it today ill let you know if it makes any difference.

 

[jaxbchangler]

Re: Need some prop advice!?

yeah the 9'' pitch helped a lil but not enough so i think im gonna try an 11''

 

[steelespike]

Re: Need some prop advice!?

Sure would be better if we had your rpm and gps speed.
Your gps speed would at least give us a very rough rpm.Some s cells have a gps app.
If you lug the motor you will have poor performance and over time premature motor problems.
If you routinely over rev you may end up with pieces of motor in your hand.

 

[jaxbchangler]

Re: Need some prop advice!?

gps speed is 7mph with a 9" pitch