posted 12-30-2005 01:01 AM ET (US)        

My question is: The new prop was accompanied by a Mercury Flo-Torq II hub kit (835257K 1), which may not be designed to fit my Yamaha motor. Any specific information on what kind of conversion hub kit I'll need (and its approximate cost) would be appreciated, as well as advice on the best place to purchase it. I don't want to just walk into my Yamaha dealership unarmed with some facts and prices, if you get my drift.

Thanks in advance to all, and special thanks again to the thoughtful donor. I'll report on my tests when the weather breaks, if it ever does.

posted 12-30-2005 10:13 AM ET (US)            

They list the hub kit as #835271Q2.

posted 12-30-2005 11:04 AM ET (US)            

Best wishes for the New Year, my friend.

posted 12-31-2005 12:38 AM ET (US)            

Are you saying that with this hub kit I've already got what I need? Are there different Flo-Torq II hub kits for different motors, or is the thing I've got some sort of universal adapter? I'm concerned since the large box the prop came in has the following printed admonition: "If purchased for a non-Mercury engine, see your dealer for the appropriate hub kit."

I'm dying to get outside and fool around with the new prop, but we're in the midst of a very serious storm out here, with substantial flooding and power loss, and I'm awaiting some dry weather to yank the old prop and see if this thing fits. I'd sure like to know definitively one way or the other.

posted 12-31-2005 10:02 AM ET (US)            

Mercury's Flo-Torq application chart is ambiguous. For starters they do not list Tony's motor at all. My experience is that Mercury and Yamaha motors will take the same props which is what Dick is suggesting.

Flo-Torq hub kit #835257K 1 *is* for MerCruisers but it is also for virtually all Mercury Outboards from 60 hp and up. I have a copy of the Flo-Torq application chart that I printed a couple months ago and it confirms this.

However, looking at the chart online this morning I see they have now substituted part number 835257Q 1 (what Dick has cited) for the 60 hp and up Mercury Outboards while maintaining 835257K 1 for the MerCruisers.

The weird thing is that these kits are (apparently) the same. A Flo-Torq hub kit is a collection of different parts. What distinguishes one kit from another may only be one of these parts. Examining the list of parts for both kits I can discern no difference whatsoever.

posted 12-31-2005 10:40 AM ET (US)            

Happy New Year, you Whalers. We're about to turn the corner on this weird, often disasterous year. Best luck to all of us in the coming one, and keep looking for that rainbow sign*.

Tony

posted 12-31-2005 05:33 PM ET (US)            

http://i22.photobucket.com/albums/b309/elaelap/Vengeanceprop008.jpg

The splines (if that's what they're called), are in perfect register with the drive shaft, the nut and lock washer fit right, so I think it's a go with this hub kit. Naturally I don't have a torque wrench so I sorta estimated how tight the nut should be. The manual calls for 55 lbs of torque. I think one way of gaugeing whether I got it tight enough is the distance between the after part of the drive shaft housing and the forward portion of the prop itself. As you can see in the photo, I've got them just about exactly lined up...is this correct, or should the forward portion of the prop tuck some into the drive shaft housing? Continued thanks for everyone's help.

Tony

posted 12-31-2005 07:05 PM ET (US)            

Thanks again, guys. Now for some decent weather so I can test this thing.

posted 01-01-2006 11:10 AM ET (US)            

In Tony's case he used everything that came with his Mercury hub kit and it all fit perfectly.

posted 01-04-2006 06:03 PM ET (US)         

It is not necessary to purchase a Yamaha specific hub kit to install this prop. In the parts listing, the only thing that is different is the addition of a "space washer" #12-850076 (whatever that is!) and the Mercury tab washer and locknut are deleted. I assume the original Yamaha nut and cotter pin are still used.

posted 01-04-2006 06:55 PM ET (US)            

Ten hours, eh, and then watch out? Well, the weather has finally broken out here and looks like it's gonna be nice tomorrow, so I've told my secretary and our receptionist about the sudden onset of a cold. I've heard that fresh air and sunshine is good for this kind of malady, so I'll be heading out to Bodega Bay tomorrow to cure my ills. The swells are still large and the seas gnarly so I'll probably stay in the harbor. I'll make sure the treatment lasts less than ten hours...wouldn't want to blow up my motor. I'll report on results.

posted 01-05-2006 10:19 AM ET (US)            

My used Mercury Offshore prop came with the Mercury hub kit and (using the Mercury thrust washer) the leading edge of the prop was not inside the lower unit housing. I bought the Yamaha thrust washer and spacer washer and the problem was solved. BTW, the Yamaha spacer washer is only necessary if want to use the Yamaha notched nut and cotter pin, otherwise the nut threads past the cotter pin hole in the prop shaft.

As Tony has pointed out, it is absolutely critical that the composite drive sleeve is firmly seated in the prop hub. This insures that the leading edge of the prop is just inside the lower unit housing.

Tony, good luck with the prop!

Steve

posted 01-05-2006 02:53 PM ET (US)            

The Trophy Plus is an odd choice for your boat. Those props are mostly intended for Bass and Flats boats that run their motors at very high elevations.

Having said that, what you want for a hub kit is really 835257K 6 which *might* necessitate the substitution of the #853555 thrust washer.

posted 01-05-2006 03:47 PM ET (US)         

On my twin 115 HP powered 18 Outrage, which can do 60 MPH, I tried a pair of these in 24" pitch and found them not easy to use. The engines could only turn them up to 4500 RPM much to my surprise. I ended up selling them, and switched to Laser II's which are ideal in twin installations. Your problem, you don't have enough speed or power to turn the minimum 20" Laser II pitch offering.

I would STRONGLY recommend you go to the mercurymarine.com prop selector program, and plug in your mumbers using the Merc 90 4-stroke, your identical engine. I'm guessing it will give you 16" Vengeance props. These should greatly improve your performance over the aluminums you are currently running. Another alternative would be the Michigan Wheel Rapture or Stilleto, in 17" pitch. On a twin engine 22, I would think your engines should be in the 2nd set of mounting holes, as recommended by BW.

posted 01-05-2006 05:03 PM ET (US)            

Because of recent flooding, the lake has risen high enough to completely flood--to the roof top--the private marina bait shop, and substantial debris including large semi-submerged logs and tree limbs were everywhere, so the speed runs were fairly short (+/- 1/4 mile), made by backtracking my much slower exploratory wake. By the way, not one other boat was observed on Lake Sonoma (except in slips in the torn-up marina) during my entire two-hour trip...that's certainly odd at any time of the year.

Now for the results: No objective, discernable change at all! My boat, carefully trimmed out and checked via GPS at various motor angles with the new prop, still struggles to reach 5600 turns (I'd like to get closer to 5800+, though the current 55-5600 is within the Yamaha manual's recommended 5500-6000 rpm range), and my speed topped out exactly the same (maybe half a mile per hour faster, which doesn't make any mathematical sense at all) as with my OE 19" prop -- 35.6 kts or a little less than 41 mph (if my math is right). Subjectively (and maybe it's because I haven't been out on the water for several weeks) the boat felt slightly quicker onto plane (she's always been real quick with one or two people aboard...3-4 seconds) and seemed to have a bit more acceleration up through maybe 45-4800 rpm, where the curve began leveling out).

This is somewhat disappointing, since I'd love to keep the shiny, sexy Vengeance prop if I could justify the change, but I'm gonna try a 16" or 17" inch prop and try to boost my turns some. Thanks again for everyone's sound advice (and yes, Peter, the prop DID loosten up a slight bit after that two-hour trial, and would have to be tightened if I were going to keep it); special thanks, of course, to the generous donor (who has still chosen not to reveal his name...here's a hint--Take Care, you Whalers ;-) ). I'll clean the prop up and ship it back this weekend.

Tony

posted 01-05-2006 05:39 PM ET (US)            

This is a very interesting result. Same speed from an 18" prop as the OE 19" prop. This tells us that it is running more efficiently with less slip. This would also suggests that because of its lower pitch it *should* be getting you on on plane easier and keeping you there at lower boat speeds, not a bad thing in and of itself.

I agree, the next prop to try would be a 17" Vengeance. Perhaps someone wants to trade their 17" for this 18"?

posted 01-05-2006 05:45 PM ET (US)            

7.6 percent with the Mercury Vengeance 18" pitch

12.5 percent with the Yamaha 19" pitch

posted 01-07-2006 03:01 PM ET (US)            

_____________________

"And you know, there was substantial fore-aft play
(maybe 3/8-1/2 inch) after the test run, and without a spacer on the leading edge of the brass thrust washer I don't know whether the thing would have ever snugged up and seated properly. I just examined the forward thrust washer of my Yamaha prop and it has a 1/4-3/8" spacer/flange cast into its leading (forward) side, so
maybe that particular Flo-Torq hub kit ISN'T the right one for my motor. Maybe I should have switched the forward thrust washers and it would have solved the problem.

That didn't really affect the brief test at all, but it would be troublesome and problematic to use the hub kit with my motor without a [+/-] quarter-ince spacer in front of that Flo-Torq hub kit's thrust washer, so maybe that's what there is in the Yamaha-specific kit, eh?

Anyway, a fascinating experiment which has me enthusiastic to keep trying, and this old dog has learned some new tricks about props, which is a good thing. Thanks again, and hope to see you soon."
________________

posted 01-07-2006 03:10 PM ET (US)            

--------------------
"7.6 percent with the Mercury Vengeance 18" pitch

"12.5 percent with the Yamaha 19" pitch

"The Vengeance is doing a much better job."
---------------------

Actually, it looks like the propellers are doing the identical job, as they both propel the boat to the same speed at equal engine speed. The concept of one being "better" because its rated pitch is lower is somewhat of an artificial result. All Mercury has to do to obtain this advantage is to mark the pitch on their propeller to be lower than the pitch marked on the Yamaha propeller. In fact, this may be the biggest difference between them.

posted 01-07-2006 03:12 PM ET (US)            

I don't think so. If you needed a spacer in front of the prop, then in the absence of said spacer the prop would have been making contact with the gearcase and would have been a big chewed up mess and this was not the case.

posted 01-07-2006 06:22 PM ET (US)            

Clear as mud? I guess I better give up on my dream of becoming a technical writer until I at least understand the difference between a nut and a bolt ;-)

My conclusion is sound, I suspect. That particular hub kit is wrong for a 2004 Yamaha 115 four stroke EFI outboard motor.

posted 01-07-2006 06:41 PM ET (US)            

Hub kit #835257K 1 uses thrust washer #835467 1. This thrust washer is tapered on the inside. I know this because it's the same thrust washer I use on my Mercurys. In fact is exactly as you describe the yamaha thrust washer.

posted 01-07-2006 06:46 PM ET (US)            

http://www-alt.mercurymarine.com/PXImages/AccessoriesArt/494_reg.jpg

It comes with hub kit # 835257K 1 which is what (I think) Tony was using.

posted 01-07-2006 07:58 PM ET (US)            

All these thrust washers are brass.

posted 01-07-2006 08:23 PM ET (US)            

I have a Yamaha F 150 on my Outrage 18. I recently aquired a Stiletto Advantage II prop 14.25 x 19 (without flo-torque) from one of our own. This prop was for a mercury 150 and after purchasing the appropriate thrust washer and spacer (as discussed above) it installed perfectly on the Yamaha. After ~ 12+ hours of running with this prop all is well and I am very happy with it. However, my question is even with the ECM in the F 150, how does the engine know that it is a prop designed for mercury or are stilettos safe? Even if the Stiletto is safe, how would the engine know what prop is on there. I'm not trying to make a joke or be a smarty, I'm just trying to understand this situation. Thanks in advance,

posted 01-08-2006 10:12 AM ET (US)            

Here are some photos of my Yamaha thrust washer which show the protrusion you are referring to:

http://photobucket.com/albums/y39/91Whaler/Yamaha%20Thrust%20Washer/

I assume this is the same thrust washer you have, and if so, is the Yamaha, not the Mercury thrust washer.

Prop wise, I would seriously consider the 4-blade Mercury 17 pitch Offshore/VenSura for your boat.

posted 01-08-2006 10:59 AM ET (US)            

Again, the important bottom line here is that if one is planning on running Mercury props on Yamaha motors it is necessary to get the proper Flo-Torq II hub kit, and this one wasn't it (though it served perfectly well for a brief trial run).

posted 01-08-2006 11:19 AM ET (US)            

Tony, you keep making a point of saying the Yamaha thrust washer is tapered to match the taper of the propeller shaft, but so is the Mercury thrust washer, or at least #835467 1 is (photo linked to above.)

posted 01-08-2006 12:04 PM ET (US)            

Tony

posted 01-08-2006 12:25 PM ET (US)            

http://i22.photobucket.com/albums/b309/elaelap/hubkit003.jpg

Oh, I guess I better warn you that this sketch is NOT TO SCALE ;-)