Looking at getting a new stainless steel prop for my 2008 Yamaha 4stroke 50hp.
My question is what pitch would be the best? And how do I find out the if it’s a 13 tooth spine or a 15 tooth spine. Looking at somethings online and holy options. thanks in advance
Matt.
Count the splines on the shaft. Keep in mind that you won’t gain a ton of performance vs an aluminum prop with a 50hp on top end. Biggest gains are with over 150hp engines that have the power to cause the blades to flex on a aluminum prop. If you are looking for a better hole shot look at a prop like the mercury tempest that have adjustable plugs that you can adjust the slip on takeoff to get your motor in it’s ideal rpm range at takeoff.
The Lund Experience had a segment talking about propping mid range motors such as yours.
If you go to the Mercury Prop Selector they give options specifically geared to your wants. I believe the boys had a 4 blade spitfire on the 60hp they were running on the show they said performed really well. It is a show for advertising though, so take it FWIW.
Thanks guys. Just looking for a new prop figured I would go stainless. But if I am not going to see that much of a difference maybe I will just consider a new aluminum. Thank you.
Well, the other benefit of SS is durability. If you run sandy areas, you’d get a much more durable prop with SS.
You’ll see a slight performance increase I think, but you’ll mostly only note it on holeshot and maybe a very small increase in speed, but as someone else said, not the bigger gains seen on higher HP motors.
As mojo said – you’ll want to remove your prop to count the number of splines. As far as pitch, you’ll want to share what pitch prop you’re running today first – prop pitch is very dependent on boat & load and isn’t a one size fits all approach. Check the back side of your prop blade for something like 13×15 – the 15 in this case would be your pitch; otherwise, when you remove your prop to see how many splines you have, look under the thrust washer – there should be some numbers stamped there, one of them with a P after it – that’s your prop pitch.
Well, the other benefit of SS is durability. If you run sandy areas, you’d get a much more durable prop with SS.
But on the flip side, if you hit a rock you have a good chances of damaging some of the components in the lower unit as the SS doesn’t have the give that aluminum has.
I have the same motor but a 2005 model and kicked this question around quite a bit and everyone I talked to said they would shy away from SS for that motor so I never went ahead with it. It kind of sucked though last spring when I hit a ice house block at just over idle speed and dinged the prop. A SS would have never dinged and I doubt it would have caused any damage to the lower unit. 
<div class=”d4p-bbt-quote-title”>Ralph Wiggum wrote:</div>
Well, the other benefit of SS is durability. If you run sandy areas, you’d get a much more durable prop with SS.But on the flip side, if you hit a rock you have a good chances of damaging some of the components in the lower unit as the SS doesn’t have the give that aluminum has.
True, but that’s what the hub is supposed to do. 
The biggest benefit of SS prop is that the fins don’t flex as much under high torque conditions. It is my personal opinion that 50 HP will not have enough power to show an appreciable difference between SS and aluminum. I wouldn’t consider the added expense of SS prop until you start getting over 100 HP.
The newer breakaway hub inserts give you the best of both worlds when using stainless props.
The rubber hub is inexpensive and the part that gives on impact.
Older motors did not have this design feature.
If you buy a yamaha stainless prop I think the hub is pressed in, so if you spin the hub you need to bring it in to a prop shop to have the old one replaced.
For your boat specs, quick google shopping has Spitfire going to be $150ish, and a SS Vengeance prop with hub $375ish.
Will the SS be that appreciable difference for that amount of $$?
To each their own.
You have a 13 spline prop shaft.The Mercury spitfire prop is a real good one.If you can swing it,the Yamaha black stainless will be the best performer.
Thanks for the info. Much appreciated.
You have a 13 spline prop shaft.The Mercury spitfire prop is a real good one.If you can swing it,the Yamaha black stainless will be the best performer.
I don’t get that, How is a painted SS prop more expensive and better than a polished SS prop?
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