# Gheenoe LT10 & Suzuki 9.9 / 20 hp Set Up



## taw1126 (Aug 28, 2021)

Hoping to get confirmation that I'm on the right track getting our LT10 set up. Has a Suzuki 9.9 short shaft on a Vance jack plate and I'm using a Hardline tach + cell phone (Waze) to get my numbers.

First time we ran the boat WOT I was paying attention to the speed but not the tach. We were getting ~19 mph and then I decided I needed to lower the jack plate (really for no good reason & again without watching the tach much). That dropped our speed to 13 - 15 mph at around 5,200 rpm. So I raised the jack plate, paid more attention to the tach, and got back to ~19 mph at about 5,450 rpm. Raised the jack plate another 1/2" and yesterday was hitting 5,640 to 5,730 rpm (did not cause an over-rev on the motor so maybe the tach is not reading exactly right). Smashed my phone earlier in the morning so I did not get speed but the boat definitely felt faster.

Max rpm on this motor is 5,700 rpm. I need to verify speed, but it seems like this is the sweet spot as far as motor position? 

We've got just under 5 hours to go until oil / filter / gear oil change and at that time I'm installing a 20 hp ECU & restrictor plate so new variables will be introduced. Thought is that if I get the motor positioned right we'll only need to change prop pitch. Sound reasonable?


----------



## Kirc (Jan 18, 2020)

assuming this motor is manual trim & manual jackplate? You _also _have the motors fixed trim positions (plus shallow water) to work with. What you will likely discover is two different "trim" positions, 1) when alone and 2) with others.


----------



## taw1126 (Aug 28, 2021)

Yes manual trim & manual jackplate. We did try different trim positions before, but not since making this last adjustment. I think it's at a happy medium but you are correct...weight distribution in this little boat makes a BIG difference. Me sitting on the rear deck vs. standing uncomfortably close to the grab bar can have ~300 rpm impact.


----------



## taw1126 (Aug 28, 2021)

Okay I think I've gotten everything there is to have out of this set-up. With a functional phone I was able to confirm 20-21 mph with just me in the boat, running very close to the 5,700 rpm redline. Did the 20hp ECU and restrictor plate swap when I got home, so with the new 6,300 rpm limit prop pitch will surely be the next thing I have to figure out.


----------



## Celicacy (May 16, 2012)

I have a lt10 and had a 9.8 tohatsu and no Jackplate was getting 21mph. Bought a 20hp tohatsu and came with a 11.5pitch prop and getting around 30 with a vance jackplate. Im hitting the rev limiter. bought a 13pitch prop and speed is still about the same and still hitting the rev limiter. I didn't find a 14pitch prop so might try stainless. I'm going to sell the 11.5 prop if you're interested. email me [email protected]


----------



## GSSF (May 25, 2013)

Celicacy said:


> I have a lt10 and had a 9.8 tohatsu and no Jackplate was getting 21mph. Bought a 20hp tohatsu and came with a 11.5pitch prop and getting around 30 with a vance jackplate. Im hitting the rev limiter. bought a 13pitch prop and speed is still about the same and still hitting the rev limiter. I didn't find a 14pitch prop so might try stainless. I'm going to sell the 11.5 prop if you're interested. email me [email protected]


Love the 9.8 Tohatsu. For your 20 hp, can you find a 13 pitch with a slightly larger diameter? That helped me.... I was in the rev limiter with my 9.8 Tohatsu on my johnboat even with a 9 pitch 8.5 diameter. I went with a 8.9 diameter 8.5 pitch and it is perfect. Just a bit more blade surface and diameter made all the difference. But I would LOVE a stainless prop.

Many props for that 20 Hatsu are a 9.25" or 9.5" diameter. The Solas aluminum prop for that boat is a 10" diameter.... maybe that would work.

That said, the stainless prop is the way to go because you don't lose much pitch while under load, like you can with an aluminum prop (due to blade flex).


----------



## Celicacy (May 16, 2012)

GSSF said:


> for that 20 Ha





GSSF said:


> Love the 9.8 Tohatsu. For your 20 hp, can you find a 13 pitch with a slightly larger diameter? That helped me.... I was in the rev limiter with my 9.8 Tohatsu on my johnboat even with a 9 pitch 8.5 diameter. I went with a 8.9 diameter 8.5 pitch and it is perfect. Just a bit more blade surface and diameter made all the difference. But I would LOVE a stainless prop.
> 
> Many props for that 20 Hatsu are a 9.25" or 9.5" diameter. The Solas aluminum prop for that boat is a 10" diameter.... maybe that would work.
> 
> That said, the stainless prop is the way to go because you don't lose much pitch while under load, like you can with an aluminum prop (due to blade flex).


Thats a good idea! I will call solas and hopefully they have a 10" diameter. I looked on their website and didnt see it when i put in my motor info. Thanks man!


----------



## GSSF (May 25, 2013)

Celicacy said:


> Thats a good idea! I will call solas and hopefully they have a 10" diameter. I looked on their website and didnt see it when i put in my motor info. Thanks man!


I could have sworn I saw a 10 inch diameter option for your application.... I hope you can find something. Solas props are a good bang for the buck. The larger diameter prop I found for my motor is made by Polaris Propeller. It gave me the 8.9 diameter as opposed to the Solas 8.5 diameter. Good luck.


----------



## taw1126 (Aug 28, 2021)

Celicacy said:


> I have a lt10 and had a 9.8 tohatsu and no Jackplate was getting 21mph. Bought a 20hp tohatsu and came with a 11.5pitch prop and getting around 30 with a vance jackplate. Im hitting the rev limiter. bought a 13pitch prop and speed is still about the same and still hitting the rev limiter. I didn't find a 14pitch prop so might try stainless. I'm going to sell the 11.5 prop if you're interested. email me [email protected]


I appreciate the offer but I have an OEM 9.25 x 11 ordered. Researched the topic until my eyes bled and that seemed to be a good choice...I'll report back after I know how it works.


----------



## taw1126 (Aug 28, 2021)

I swear if it was a Christmas gift I wouldn't have seen this prop for another 2 weeks but boats.net got this thing to me in a big hurry. Factory / OEM 9.25 x 11 is now installed and it looks like we're going to have 82 F high on Christmas Eve so I should be able to test it out this week.


----------



## taw1126 (Aug 28, 2021)

I still have some fine-tuning to do on the jack plate and possibly trim but I think prop pitch can be put to bed. With 450 pounds of passengers the Suzuki 9.25 x 11 x 3 gave us 6,160 rpm and a top speed of 28 mph. I'm entirely content with that out of an LT10.


----------

