Prop Help

Bennettc

Seaman
Joined
Mar 6, 2009
Messages
57
I tried asking for help in the prop section, but didn't get a response. I am looking to replace my current prop as it is pretty beat up and I would like to use it as a spare. It also seems like I need to lower my RPM's. I am mainly concerned with performance with a full load (4-6 adults). I would be open to an big eared or 4 blade prop if it would help.

Please let me know what you guys think would be a good prop to move to.

Thanks!

Here is my info:

1) Performance issue you are trying to correct. Less strain on motor and more speed with full load.
2) Current prop manufacturer, model, aluminum or stainless as a minimum. Michigan aluminum-386909
3) Current prop diameter and pitch (required). 12.5 x 13
4) Wide open throttle RPM and speed with an average load (very helpful) 6100-6300. 14mph
5) Engine/drive make, model, year, and HP johnson 40hp 1990
6) Boat make model, year, length and weight Tracker Bass Buggy 18ft
 

EGlideRider

Lieutenant Junior Grade
Joined
Dec 14, 2008
Messages
1,000
Re: Prop Help

Depending how 'beatup' your current prop is, that could easily be the reason for the high R's.

I would try a 13X13 or 13X14.
 

crb478

Lieutenant Junior Grade
Joined
Dec 6, 2006
Messages
1,036
Re: Prop Help

I am a fan of the 4 bladed props on pontoons. For your set up I would consider a 15 pitch prop, that should get you in the 5500 rpm range where you want to be and pick up a little speed as well.
 

papasage

Senior Chief Petty Officer
Joined
Jan 12, 2003
Messages
785
Re: Prop Help

my pontoon has a 4 blade 11 pitch 12 mph. tried a 16 pitch 3 blade ss and it would hardley moove the 24 ft pontoon probabley at a good walking pace .
 

Bennettc

Seaman
Joined
Mar 6, 2009
Messages
57
Re: Prop Help

Thanks for some of the input. My current prop has a couple small chunks taken out of one of the blades and my be slightly bent. When I do some of the prop selections I don't get any results for a 13x14.

I may go with a new 12.5x13 and see how it does.

Does anybody know what the target RPMS would be for my motor? The model number is TJ40ELESR.

Prop.jpg
 

EGlideRider

Lieutenant Junior Grade
Joined
Dec 14, 2008
Messages
1,000
Re: Prop Help

I don't think that prop is beat up enough to cause the high RPM's. I still recommend the 13.
 
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