Prop for 24' Pontoon, 65 HP Johnson

[hvymtl939]

Just like the title says, I need a prop for the 65 HP Johnson that is going on my 24' Pontoon. Obviously I'm not expecting a speed demon. What would y'all recommend?

 

[Merc40hp]

hvymtl939, there are several prop selector sites on line that can assist you in getting a best fit/function/performance prop for your set up but the suggestions are only as good as the data you input into the calculator when prompted. Look at https://www.mercurymarine.com/en/us/propellers/selector/#/step-one. You really need some basic information to get good results. What size and pitch prop are you currently running? What is your RPM's and speed at WOT? unless you can answer these questions the best prop for you setup will be a trail and error affair.

 

[MH Hawker]

a 7, 9,11,13 is common for that size and hp will need a bit more info to make a suggestion, need present pitch, WOT rpm and GPS speed

 

[hvymtl939]

Well, the motor is not on the boat yet, and the prop that is on there is scrap at best, so I am going to need to buy one to be able to go out. So I need a "close enough" recommendation to at least get me on the water.

 

[MH Hawker]

i see so your going to gamble on a 75 to 100 dollar prop as a pure WAG a 11 pitch

 

[papalobster]

I think the point is he doesn't know where to start and is looking for recommendations. Being new here I'm going to answer with what I have and what I know. I have a 24 foot Northwoods with a 40hp OMC (2 cyl) running a 13p standard prop. It will spin at 5200-5300 WOT and give me 18 mph unloaded with clean logs. I am in process of rebuilding a 60 hp twin to replace the 40. That 60 came with a 17p prop. I put the 17p on the 40 just to see what would happen 3300 WOT at about 9 mph. That is bad for motors.

Using what I did, I would wager a 13p might be a better fit for your application. It may be possible to over rev with the 11p.

But it also depends on your intended use. A toon on a small lake will most likely just putt around without ever needing to get anywhere in a hurry so an 11p at part throttle would be fine. We toon on Lake Winnebago and can cover 80-90 miles a day, so I see more WOT stuff. We have a nice state park on the opposite end of the lake 27 miles away.

An 10p or 11p 4 blade high thrust prop would be better, but I don't know if they are available for a 65hp Johnson.

 

[hvymtl939]

I think the point is he doesn't know where to start and is looking for recommendations. Being new here I'm going to answer with what I have and what I know. I have a 24 foot Northwoods with a 40hp OMC (2 cyl) running a 13p standard prop. It will spin at 5200-5300 WOT and give me 18 mph unloaded with clean logs. I am in process of rebuilding a 60 hp twin to replace the 40. That 60 came with a 17p prop. I put the 17p on the 40 just to see what would happen 3300 WOT at about 9 mph. That is bad for motors.

Using what I did, I would wager a 13p might be a better fit for your application. It may be possible to over rev with the 11p.

But it also depends on your intended use. A toon on a small lake will most likely just putt around without ever needing to get anywhere in a hurry so an 11p at part throttle would be fine. We toon on Lake Winnebago and can cover 80-90 miles a day, so I see more WOT stuff. We have a nice state park on the opposite end of the lake 27 miles away.

An 10p or 11p 4 blade high thrust prop would be better, but I don't know if they are available for a 65hp Johnson.

Thanks for the feeback. You're right. I don't know where to start since I have no baseline to go off of. There's a guy on our local craigslist with a 13p in great shape for $45, so I'm going to shoot him an email.

98% of our boating will be on local Kansas lakes, so rarely will we be on a lake bigger than 10k acres. We might make a trip to Lake of the Ozarks once or twice a season, so that would be a lot of WOT, but most of it will just be putting around and hanging out on smaller lakes.

 

[Sea Rider]

How shot is current prop, is hub spun, are blades not bent ? If with just nicks, paint deterioration you should test that prop as a starter on a wot spin as currently loaded, once achieved wot rpm is known can subtract that reading from max wot rpm range factory stated to know now many less pitch sizes need to go after.

To test any prop professionally, you need a tach, without it combo is prematurely dead. OB needs to run at max wot rpm range, once there can throttle at the rpm/speed you like most. The engine will surely thank you..

Happy Boating

 

[hvymtl939]

How shot is current prop, is hub spun, are blades not bent ? If with just nicks, paint deterioration you should test that prop as a starter on a wot spin as currently loaded, once achieved wot rpm is known can subtract that reading from max wot rpm range factory stated to know now many less pitch sizes need to go after.

To test any prop professionally, you need a tach, without it combo is prematurely dead. OB needs to run at max wot rpm range, once there can throttle at the rpm/speed you like most. The engine will surely thank you..

Happy Boating

Current prop is beat to hell, bent, etc. I wouldn't feel comfortable even testing with it. When I bought the motor, guy ran it for me on the stand, and it ran great. However, part of the sale was he was taking the prop off of this motor to use on his new one, and gave me this banged up prop with it to take home, just to keep the shaft safe.

 

[Sea Rider]

Check if possible which prop was factory delivered with that OB, should be a medium size pitch, can go say 2 less sizes in pitch to pull wot revs up as you're running a toon, will perform much better.

Happy Boating

 

[phillnjack2]

Buy the 13 pitch and go from there, its a good baseline and you can then see if you need a bigger one or smaller one of even better one of same size

 

[hvymtl939]

Ended up picking up a 13p. We will see how it does. I'm not expecting serious speed out of this thing.