# Tohatsu 20HP. Prop Help/recomendation



## mxmike (May 4, 2018)

I have a 2017 Tohatsu 20HP. (carbed) long shaft/tiller with a 9p prop. CMC-PT-35 trim plate. On a 1754 Grizzly.

I swear I'm hitting the rev limiter at WOT. Motor bucks/bumps at WOT and I have to back off the throttle just a little to smooth it out. Have a Tiny Tac, but it's all over the place 6500-7000 RPM's
I'm getting around 22MPH with a good hole shot.

Should I go to a 10P prop or jump to an 11P from the 9p?
Thanks


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## DaleH (May 4, 2018)

Here you go ...

https://www.forum.tinboats.net/viewtopic.php?f=4&t=37433

When done w/ the calculator, check the box to have them review the data. If your specific boat is not listed, then find a comparable brand of the boat and use that. Like for me a prokraft was not listed, but I used an almost exact model Lund in the calculator tool and it worked fantastic!


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## mxmike (May 4, 2018)

Thanks for the link. I have used several different prop calculators. They all give a range of 9's to 11.5P.


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## DaleH (May 4, 2018)

mxmike said:


> Thanks for the link. I have used several different prop calculators. They all give a range of 9's to 11.5P.


What is the rated max RPM of that motor, by the book?


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## Bateman (May 7, 2018)

Go with the 11. One inch in pitch is not going to offer enough to bring your RPMs down if you're bumping limiter, IMO. Also, if you are over revving, your engine should have an audible and or red light that comes on. Mine did when I went through the same.


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## mxmike (May 7, 2018)

Bateman said:


> Go with the 11. One inch in pitch is not going to offer enough to bring your RPMs down if you're bumping limiter, IMO. Also, if you are over revving, your engine should have an audible and or red light that comes on. Mine did when I went through the same.




My motor is a tiller and the manual says there is no audible alarm. Haven't noticed the light coming on. I'm going to have to hook (a real tac) to see if for sure I'm hitting the RL. But it sure feels/sounds like it is. Thanks


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## Bateman (May 8, 2018)

mxmike said:


> Bateman said:
> 
> 
> > Go with the 11. One inch in pitch is not going to offer enough to bring your RPMs down if you're bumping limiter, IMO. Also, if you are over revving, your engine should have an audible and or red light that comes on. Mine did when I went through the same.
> ...



That's correct I believe mine was just a light. I'd put my money on you being on the limiter. An aluminum Solas will run you $60-70 so it's a fairly cheap gamble as far as picking the right pitch. Have an 11 for those days where you are light loaded and keep the 9 for hunting season or what not where you have her sitting heavy.


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## mxmike (May 8, 2018)

Bateman said:


> mxmike said:
> 
> 
> > Bateman said:
> ...



Yeah, Found/bought a new Solos 9.25 X11 online for $52. You are right, easier, cheaper to just buy another prop and give it a shot. Thanks !


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