Hi all.
is anyone able to tell me what the purpose of the Yamaha Propeller Deflector Ring is? It's for a 9.9 high trust outboard and I believe it goes on the front facing side of the propeller.
I currently don't have it attached and not sure what it's purpose is.
having troubling finding the answer online. Can see them to buy online, but no description on what it's purpose is.
Thanks

To protect the propeller blades from hitting something like shallow sand/rock and logs. If you hit them you will damage the prop. I hit a log with my 2HP motor and it broke the split pin in the hub.
It may have some value in protecting objects and your legs from getting in the way of the propeller too.

Thanks Phil. Although I'm not talking about a prop cage or protector, I am talking about a plastic ring that is used for cavitation purposes or something like that.

www.crowleymarine.com/parts/441510.cfm?gclid=Cj0KCQjw6J-SBhCrARIsAH0yMZi9r6FsNG6LU-INwsVdtm-ZGHzQeVrktj_YNbXzOsHOQp1TchSr5mQaAn1aEALw_wcB

See here - looks like they are for the "Dual Thrust" props which have high thrust in reverse as well as fwd due to the function of the hub design or in the case of a hub with this deflector ring fitted - exhaust gases are deflected away from the blades when in reverse so that the blades bite clean water. Expect phoning Crowley Marine will confirm.

www.crowleymarine.com/parts/450862.cfm

and 4th pdf page of this

static.perfprotech.com/files/store/app_themes/ppt/images/product-specs/Yamaha-Propellers.pdf

Thanks R13. That what I was wanting to know, so thank you.
So it sounds like it's main use is in reverse, that's good to know as I currently don't have mine attached, but will get it on.
Thanks

R13 is right, its a feature of the high thrust, and to do with the exhaust and reverse.
Also, treat the prop as a consumable item, with a lifespan.

It drives through a rubber moulded in doughnut, which will in the end perish, leaving maybe 10% of drive left based on friction b/n inner and outer hub.
We just managed to slowly motor back to the mooring one time, and now keep a spare onboard, and change it about every 2 years.
great outboard.

Thanks CrustySailor. I was also going to ask about that rubber seal/mould. So it does ware overtime and need replacing?
Is this not a separate part? Or best of buying an entire new prop that comes with it?
my current prop does not have any markings on it that I can see. No prop specs marked on it at all.
did they come with a certain spec prop and I can simply buy the same one?
thanks

you just need to know the model number, on the sticker just near the leg pivot.
Having said that, I think all 9.9 high thrust 4 stroke props are the same.
No, separate donut part sorry, the rubber is formed in the prop when made, like an infill.
You cant really suss out its condition either (well, I couldnt).
But its easy to change.
Then do your impellor too, which involves dropping the leg off (4 bolts, and disconnect the throttle lever) but thats for another day.
Also, take some whipper snipper line, and insert it into the pee hole teltale, it will clear any crusty salt, so you can ensure the impellor is pumping.

And finally, at the bottom of the leg, are 2 small 'drain covers', held in with a self tapper, one on each side. They cover the water inlet water intake. In the past, I have found some of the impellor pump vanes, which was a good sign to change the impellor.

Thanks again Crusty. Very helpful and I will check all that out.
I am pretty impressed by the amount of tourque/thrust these outboard produce. Able to move my 3tonne cat pretty easily.
How are these outboards for running for a few hours straight? I may need to motor for about 4 hours over the next weekend. As long as she is in good nic I am hoping it will be ok?
Thanks

hey Ben, what cat do you have?
Mine is a Schionning Wilderness 9.3m, and the Yamaha pushes that along fine.
If yours is in a pod, or otherwise unaccessible, the other thing you might consider is adding a temperature guage, especially if you cant see the telltale.
I'll find some pics.

Select to expand quote

BenCroop said..
Thanks again Crusty. Very helpful and I will check all that out.
I am pretty impressed by the amount of tourque/thrust these outboard produce. Able to move my 3tonne cat pretty easily.
How are these outboards for running for a few hours straight? I may need to motor for about 4 hours over the next weekend. As long as she is in good nic I am hoping it will be ok?
Thanks

2 years ago I ran my 2stroke 9.8HP outboard for 22 hours non-stop one weekend and then about 20 hours non-stop the next, for a delivery trip. 200 miles. Worked fine, and still works fine.

same as Phil.
My boat was delivered from QLD to vic, and had long periods of motoring when the wind died out.
I wasnt fussed about engine hours or anything, just to get the boat here.

I did notice when it was arrived, the engine cowling cover was cracked open abit just to allow some extra cooling, the last few hours where in sheltered waters. I think fuel wise, it used about 2l/hour from memory (4 stroke).

Nowdays its only used in and out of the mooring, the boat sails quicker than motors.

A 2.5hp Tohatsu has crossed the Atlantic.

www.tohatsu.com/marine/na/news/seiko.html

motoring 21 hours/day for 27 days is a good effort.