Yamaha 50 HP Prop Replacement

[RAyres]

I Have a 24' Pontoon with a Yamaha 50TLRD on it. Last weekend I spun the prop and in the market for a new prop and getting the old props hub replaced for a spare. The current prop I have is a 12 1/4 x 9 aluminum which give the boat decent performance and WOT is around 5000-5500 RPM. I have found many replacement aluminum props for around $75 -$100, but have the interchangeable hub system. But I also found a 12 x 9 Stainless prop for $230. My Question is will i notice any difference if I go with the Stainless prop even though it it is a 1/4" smaller. I know that a stainless prop is more efficient and was thinking that would offset the 1/4" difference. Any advise is appreciated.

 

[steelespike]

Re: Yamaha 50 HP Prop Replacement

I would be inclined to go with a Solas 4 blade In a 9" largest diameter available.
The 4 blade will b e smoother, will ventilate less and will handle better around the dock.

 

[RAyres]

Re: Yamaha 50 HP Prop Replacement

I would be inclined to go with a Solas 4 blade In a 9" largest diameter available.
The 4 blade will b e smoother, will ventilate less and will handle better around the dock.

Will a 9" diameter prop still be able move my 24' pontoon boat? What pitch do you recommend? The 3 bladed prop i have now is pretty smooth and handles good around the dock.

 

[steelespike]

Re: Yamaha 50 HP Prop Replacement

I mean a 9" pitch. Normally I wouldn't mention diameter as it simply follows the design and if intended for your motor would be right.
It is a good idea with a pontoon to try to stick with a larger diameter if available however.

 

[Sunnyjen]

Re: Yamaha 50 HP Prop Replacement

A larger diameter prop will give you more push for the toons. Sounds like you are just gessing at he pitch you need. I recommend you find out what the RPM operating of your motor is and go from there. I have a Yamaha 90F. RpM range is 5000-6000 while developing 90HP at 5500. At wide open throtle (WOT) with a 13.75 x 14 cupped prop I will get 5800RPM and 27 mph. If I drop pitch to13 I'll slow the boat, but will have more pulling power. I don't want to slow the RPMs below the 5500 mark. If I increase pitch say to 15, I'll increase top speed but have less pulling power to bull tubers or hawl lot of passengers. Again I don't want to go above the 6000RPM range. Hope this helps.

 

[RAyres]

Re: Yamaha 50 HP Prop Replacement

I have a couple options to go with now, but I don't want to affect my performance any. I have good performance now with the 12.25" X 9" 3 Blade aluminum Prop. And now I have 3 options and just trying to figure out the best.

1. Solas 3 Blade Aluminum Prop Size : 12.1" X 9"

2. Solas 4 Blade Aluminum Prop Size: 11.8" X 9"

3. Solas 3 Blade Stainless Steel Prop : 12" X 9"

Just wondering the Positives and Negatives with switching to these props regarding the material differences, prop diameters and number of blades.

I have read in places the when going to a 4 blade prop you should decrease the pitch by 1" but the don't make one in an 8" pitch. I know going to a smaller diameter will affect the ability to move heavy loads so will going to SS counteract this or increasing to a 4 Blade counteract this better. Any help will be appreciated, and I'm sure it might bring up more questions.
Thanks, Robert

 

[Sunnyjen]

Re: Yamaha 50 HP Prop Replacement

Yamaha put a 50TLR on a GE Suncatcher and used a 12 1/4x9. WoT 5600 and 19.3MPH. Sounds like you have the correct prop now. If you want to change, what do you want to achieve. Have you changed anything on the boat, added anything like a third toon. I've tried four blade props and would prefer 3 blade and cup it to eliminate any cavitation problems. If you want to see the performance bulletin, google GE Yamaha Performance Bulletin. I've found that you should go with the largest diameter prop the boat will handle. More diameter more water to grab and push your displacement boat.