40hp yamaha on a pontoon prop??

[timmyg]

I've been reading through the forum and haven't seen tha answer that I need.
I have a 24' pontoon and the 55hp johnson that I had on it lost compression on the top cylender. I have a 16' aluminum fishing boat with a 1988 40hp Yamaha that I'd like to put onto the potoon. The problem I have is that I don't know what pitch the prop is that is on the Yamaha. I'm sure I'm going to need a new lower pitch prop but not sure what pitch would be best for this motor/pontoon combo.
Thanks in advance, Timmy

 

[steelespike]

Re: 40hp yamaha on a pontoon prop??

The best way to make a prop selection would be to run the present prop and get us the max rpm and speed by gps.Taking a guess start with a 4 blade 11" pitch It could be a little light but better to be a little under.
Also be sure the 40 is a long shaft. (20")

 

[Kamdyn]

Re: 40hp yamaha on a pontoon prop??

I've been reading through the forum and haven't seen tha answer that I need.
I have a 24' pontoon and the 55hp johnson that I had on it lost compression on the top cylender. I have a 16' aluminum fishing boat with a 1988 40hp Yamaha that I'd like to put onto the potoon. The problem I have is that I don't know what pitch the prop is that is on the Yamaha. I'm sure I'm going to need a new lower pitch prop but not sure what pitch would be best for this motor/pontoon combo.
Thanks in advance, Timmy

Timmyg let me check what I have on my Yamaha 40 and ill post back, I have a really good pitch prop that works good on heavy load. I have a Princecraft deluxe with all the bells and whistles so I need that certain pitch to push my boat. Also take your prop off and let us know what you have on

 

[timmyg]

Re: 40hp yamaha on a pontoon prop??

thanks Kamdyn! that would be great!!!

Also steelespike, I believe it is a long shaft. It is the same as the 55 that is on it now.

I removed the prop from the 40 and was able to find the #s and it is a 3 blade 13 pitch so I may get lucky there I figured it would have been higher on that light little boat.
I'll have to look but the one on the old 55 is either a 11 or 13 pitch.
I guess once I get this thing running I need to invest in a tach.

Timmy

 

[Kamdyn]

Re: 40hp yamaha on a pontoon prop??

Whats the dry weight of the pontoon boat? Because the 13 pitch will be good for that if its heavy (More thrust), Although you will get more torque with an 11 pitch (Speed). On my Yamaha I have a 13 pitch which is standard pitch I got with the motor, Hope this helps with your issue.

 

[timmyg]

Re: 40hp yamaha on a pontoon prop??

Thanks so much. That gives me a good place to start.
Well I was out running it hooked to a hose and it quit peeing (go figure) so I have to pull the foot replace the water pump. I was something I needed to do before putting it onto the pontoon anyway.

 

[Kamdyn]

Re: 40hp yamaha on a pontoon prop??

Thanks so much. That gives me a good place to start.
Well I was out running it hooked to a hose and it quit peeing (go figure) so I have to pull the foot replace the water pump. I was something I needed to do before putting it onto the pontoon anyway.

Check to see if the motor is clogged before you spend money on the pump, there might be debris in the pee lines or the motor, Unhook the line where its attached to the engine, And push a metal wire while running and see if water will gush out. It might be clogged or something, I had that problem alot of times. The lake that I regularly fish is really shallow and weedy.

 

[timmyg]

Re: 40hp yamaha on a pontoon prop??

Yeah I checked all that. I was running the motor on the muffs and it just quit peeing. I pulled the foot off and the pump was in bad shape and the housing was pretty worn so I'm going to get a kit and replace the whole pump. I took a hose and ran water up into the motor with the foot off and everything flowed good. I also flushed down through the foot.
It was something I needed to do while it was on the jon boat before putting it onto the pontoon. I don't have a trailer for the pontoon so it will be in the water all the time and I'd hate to have to change the waterpump on the water LOL

Thanks again everyone for all your help,
Timmy