Yamaha FT50 CEDL - What Prop?

[Robert]

I have no experience with the Yamaha High Thrust or Mercury Bigfoot, so I have no favorite prop for it.
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If you plan to keep the ballast full or load the boat heavily most of the time go with the lower pitch prop. If you want max speed without ballast and with the boat lightly loaded maybe use the higher pitch prop. Personally I prefer to run the top RPMs with the lowest safe prop pitch, but that is knowing that my Suzuki dealer recommended that my DF50 with 4 valves per cylinder and fuel injection likes to run at or slightly over the top of the RPM range. Other outboards may not like to run top RPMs, so ask a Yamaha dealer or the folks on this discussion who have the Yamaha if it likes to run at the top of the RPM range.
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My experience with a cavitation plate hydrofoil is that it helps level the boat, but does not increase top speed. I used the foil from PiranhaPropellers.com because it is well made of nylon in resin just like their propellers so it should not deform over time like the Dolefin does.

[Moe]

If 11"x13" means 11" diameter x 13" pitch, there's no way a 13" pitch prop should be letting the motor reach 6,000 rpm, especially at only 25kmh unless it's slipping badly. That would happen if you used a prop designed for the small gearcase F50 versus one for the large gearcase T50, and exhaust gas would be leaking out ahead of the prop causing it to slip badly. BTDT with a Michigan Wheel prop with a poorly designed thrust washer.

Definitely look for a 14" diameter prop designed for the T50 gearcase. A 10" pitch would be a good compromise for very lightly loaded to heavily loaded. If you were going to be regularly pulling a tube, etc with the family aboard, you might even consider a 9" pitch.

FWIW, a 14"x13" pitch prop is what I use on our 60HP Mercury BigFoot on our 15' Whaler when it's heavily loaded... and at that point, it's close to half the weight of a loaded up Mac.

[Catigale]

14 inch by 10 pitch is what Art put on my BF Merc 50 ....works great (topped out at 24mph 5800rpm IIRC) when the boat was first in season

Now with the family and gear I can do 18-19 mph...

Prop works great unless you back it into rocks on Cape Cod...replacing this spring...

[shehzad]

I had been going on with the same proppellar 13 dia x 11 pitch. My engine has now completed almost 40 hours.
I used to touch 6000 RPM in the begining but now with the same weight on board, I cannot go more than 5300 RPM. Is it normal ? or is it due to the fact, before I had been running in very calm sea and now monsoon season started in our region and sea became rough ? or would there be some thing wrong with the engine?
I must remind to readers of this forum that I am having Yamaha 50 HP high thrust engine on my boat and furhter more no technical help is available from the dealer due to lack of knowledge, so I must do on my own.

[edurbin]

Shehaz,
I have the FT60. Don't know what speed it does - never checked. The prop diameter is definitely 14 inch. I think it is 11 pitch - the only number that I can see on the prop. This works well. I can get 6000 rpm with or without water ballast in. My motor has now done 100 hours.

Craig

[Robert]

With my Suzuki DF50 on a Mac26X using a Solas prop that would reach 6400 RPM (16 to 17 mph) on calm seas, make about a thousand RPMs less in 5 foot chop and only 12 to 13 mph. Testing props in good conditions is a big part of why I like to prop for the top of the RPM range with ballast full, because eventually the bad conditions will happen.