Yamaha 175 SHO

[capt lenny]

Just purchased a new 175 SHO. When I put it into gear, either forward or reverse it kind of chatters for 5-10 seconds and eventually goes away. This doesn't seem like the chatter you would experience if you were putting it into gear slowly and grinding the shift dog. My question is, should this engine shift into gear any different than the 200 HPDI that replaced? I've never heard any engine shift like this but the dealer says it's normal.

[rodbolt17]

I have heard it before on some of the inline 4 strokes.

without hearing it its hard to say.
have you tried the SDS prop?

[capt lenny]

Yamaha 175 SHO

No I haven't tried the SDS prop. Still using the Mercury Mirage prop from my old outboard. What does the SDS prop do better?

[rodbolt17]

it shifts smoother and doesn't chatter.

[boscoe99]

What you are describing sounds like what is commonly known as propeller "rattle" or "chatter".

This phenomenon is more prevalent in four strokes because they are generally quieter (noise can be heard) and they fire half as often as does a two stroke model.

The SDS (Shift Dampening System) reduces the clunking sound when shifting into gear and it also mitigates the rattling sound that can be heard when the motor is just into gear at idle RPM. The noise is not damaging but is rather a nuisance. It should go away on its own if you bump the RPM up just slightly.

Mercury Marine and other propeller makers also create a propeller with a hub that is designed to mitigate or eliminate the noise.

Here is a link to some Yamaha information that describes the SDS feature in certain of their propellers.

http://yamahaoutboards.com/sites/def..._5-FINAL_1.pdf

[capt lenny]

Yamaha 175 SHO

Thanks Boscoe99, I'm using a Mercury propeller so that makes sense. Not sure I want to spend more money on a Yamaha prop right now. Do you know the number for a Mercury hub?

[boscoe99]

Thanks Boscoe99, I'm using a Mercury propeller so that makes sense. Not sure I want to spend more money on a Yamaha prop right now. Do you know the number for a Mercury hub?

It depends upon the type of hub that you have in your current propeller. Is it the pressed in kind or the field replaceable kind? Needs to be the latter.

You might want to try the Mercury Flo Torq IV hub kit.

Quicksilver Flo Torq IV Hub Kit Mercury

Flo-Torq IV Mercury Hub Kit 835257K10

[capt lenny]

Yamaha 175 SHO

Currently using a Mercury Flo-Torq II with a Mirage Plus. From what I'm finding online it looks like Mercury is only making the Flo-Torq IV for Mercury engines. I think the splines and threads are the same and I'm thinking the only difference is the forward thrust washer. Am I correct? I know a few years ago when Yamaha and Mercury were engaged, Yamaha was using a lot of Merc lower units.

[rodbolt17]

wrong
just cause you saw it on the net doesn't make it right.

back in the day merc used some Yamaha engines painted phantom black.
Yamaha used some merc engines painted silver gray.

but they did not interchange powerheads or gearcases.

the merc f200/225 actually had a merc hood but the rest was Yamaha painted black.

the old 3cyl F40 was a silver gray merc all the way down to the unreliable motorola electronics.

[rodbolt17]

your 175SHO was shipped with the SDS prop attaching hardware.
why you have a merc prop with a Yamaha hub kit is beyond me.
actually I know why but am to polite to point it out.

[boscoe99]

Currently using a Mercury Flo-Torq II with a Mirage Plus. From what I'm finding online it looks like Mercury is only making the Flo-Torq IV for Mercury engines. I think the splines and threads are the same and I'm thinking the only difference is the forward thrust washer. Am I correct? I know a few years ago when Yamaha and Mercury were engaged, Yamaha was using a lot of Merc lower units.

The Mercury Flo-Torq IV hub kit can be used on a Yamaha simply by replacing the Mercury thrust washer with the Yamaha thrust washer. Speaking from a fading memory I think that I seem to recall that Mercury Marine offers a Flo-Torq IV hub kit that comes with the correct thrust washer in the kit.

Mercury has a top notch customer support organization. Might not hurt to call them and they can tell you exactly what parts you will need and to what torque value the propeller nut is to be tightened. 920-929-5040

[boscoe99]

your 175SHO was shipped with the SDS prop attaching hardware.
why you have a merc prop with a Yamaha hub kit is beyond me.
actually I know why but am to polite to point it out.

The Yamaha parts catalog shows only the I4 F175 as coming with the SDS hardware. The VF175 SHO comes with the standard two piece thrust washer for a SHO propeller.

Not uncommon at all however for certain boat builders to use Mercury Marine propellers on Yamaha motors. Better selection and they don't have to carry two brands of propellers.

[tmann45]

You might want to try the Mercury Flo Torq IV hub kit.
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Cheaper alternative to the Flo-Torq IV is using a RUBEX insert instead of the Mercury solid one. I'm using one on my F250XCA since Mercury does not make a prop rattle hub kit for higher horsepower outboards.
Hub Installation Guides, Rubex Interchangeable Hub Propellers

[capt lenny]

In response to rodbolt17, I run a Mercury prop on my Yamaha because Mercury makes a number of great props for different situations at an affordable price. The gently used market is full of used props at even more affordable prices. I can hardly find any used Yamaha props. Yamaha's new SHO props run about $750 verses about $525 for a Mercury. I see and know of a lot of people running Mercury propellers. I'm quite disappointed with the performance of my SHO, mainly the "impressive hole shot" that Yamaha advertises. I haven't had the chance the experience the "exhilarating top end" yet since I'm still breaking it in. I welcome all prop suggestions. To rodbolt17, send me your suggestions.