2 stroke prop v.s. 4 stroke prop

[T_Herrod]

Is there any or much of a difference between a prop for a 2 stroke yamaha 50tlra and prop for a 4 stroke yamaha f50tlra.
Thanks in advance
Tom

 

[Bondo]

Re: 2 stroke prop v.s. 4 stroke prop

Is there any or much of a difference between a prop for a 2 stroke yamaha 50tlra and prop for a 4 stroke yamaha f50tlra.
Thanks in advance
Tom

Ayuh,... Post the Numbers on 'em....

 

[muskiemike12]

Re: 2 stroke prop v.s. 4 stroke prop

I think he is asking if there are different props for 2 stroke vs. 4 stroke motors. The only difference would be if you have a high thrust 4 stroke. Those props have much bigger fins.

 

[steelespike]

Re: 2 stroke prop v.s. 4 stroke prop

The props appear identical for same year motors.And the motors appear to have the same gear ratio.
I do wonder if they might require different size props for the same application do to different power curves
and available max rpm.

 

[Philster]

Re: 2 stroke prop v.s. 4 stroke prop

Mercury does recommend different props for different stroke engines. I'm going to say it has more to do with slight differences in design to manage how the prop does in the lower RPM band. A 2-stroker is more likely to ventilate a prop or cause it to lose traction at mid-range, too.

So, the prop design (e.g. vents and size) is likely just a little different, but I would suspect it is to leverage a 2-stroker's unequaled low- and mid-range punch. It's a vastly different punch than a 4-stroker can generally offer, especially vs. a modern 2-stroker.

 

[Dhadley]

Re: 2 stroke prop v.s. 4 stroke prop

In the case of the 2 50 hp Yamaha motors you mention we would use the same style prop for either. The pitch and / or set up may be different but the style or prop model would be the same. In some cases a 4 stroke may require more prop venting to help their lack of bottom end power. A Yamaha SHO motor does not fit into that scenario.....

 

[T_Herrod]

Re: 2 stroke prop v.s. 4 stroke prop

I never thought prop selection would be so crazy. I have been searching for a yamaha performance data sheet for my boat. The closest thing i can find is a data sheet for my boat but it has a 4 stroke engine and mine is a 2 stroke.

http://www.yamahaoutboards.com/site...idthrustjetport_al_g3b-anglerv167c-f50tlr.pdf

Is there a way to run the serial number on the engine to see what it was born with?
Many thanks
Tom

 

[Dhadley]

Re: 2 stroke prop v.s. 4 stroke prop

I think what you're asking is what prop came with the motor. If you buy it as just a motor it doesn't come with a prop. If you buy the boat and motor package it probably comes with what the dealer put on. Is your boat the same as the one in the bulletin?

 

[steelespike]

Re: 2 stroke prop v.s. 4 stroke prop

I never thought prop selection would be so crazy. I have been searching for a yamaha performance data sheet for my boat. The closest thing i can find is a data sheet for my boat but it has a 4 stroke engine and mine is a 2 stroke.

http://www.yamahaoutboards.com/site...idthrustjetport_al_g3b-anglerv167c-f50tlr.pdf

Is there a way to run the serial number on the engine to see what it was born with?
Many thanks
Tom

If you check the stickys at the top of the prop forum and get us as much info as possible there are guys here that can get you setup and tell you if your setup is working. A basic setup with good performance is fairly easy. To refine it for the very best performance for your needs is a little more involved.

 

[T_Herrod]

Re: 2 stroke prop v.s. 4 stroke prop

Is your boat the same as the one in the bulletin?

Yes the boat is the same. Mine has a 2 stroke engine. The boat has no gauges so i have no idea what the wide open rpm's are. I contacted the dealer i bought the boat from and he is going to contact yamaha to try to find out what prop i should get.
Many thanks
Tom

 

[Dhadley]

Re: 2 stroke prop v.s. 4 stroke prop

Don't be shocked if the dealer doesn't get a straight answer. They may take the position that final prop selection is the dealers responsibility. They may refer him back to that bulletin you have. They may not even talk about set up and how it affects prop choice. In any case without a tach were all shooting in the dark.