Converging Ring

[Bad Wolf]

I see that there is supposed to be a "converging ring" on the propeller which of course is not on mine. Is this something unique to the Johnson props? I'm sure what I have on my motor ('84 Johnson 15hp) is not original.
It looks like I can get one for $11.00, is this something I need?

Thanks

 

[jacobxrt]

It is my understanding that since your exhaust is directed out through the propeller the converging ring is there to ensure the exhaust gets funnelled away when you are in neutral or moving in reverse, and prevents exhaust gases from entering the working area of the blades. It also helps control ventilation. If you don't get rid of that exhaust it will result in performance issues. I think the new props have come up with a new way to deal with this but if you are using an older style prop you should ensure that the converging ring is installed.

-Jacob

 

[NautiBuoys]

I believe OMC called it a converging ring and others an exhaust ring. It's purpose is to prevent exhaust gases from entering the working area of the blades so the prop gets a cleaner bite. Depending on the prop, the ring may be replaceable; I've seen some molded into the prop. Probably wouldn't hurt to replace it if you can.

 

[Bad Wolf]

The PO gave me two props, the one on the motor is black with a slight flare or bell at the trailing edge of the prop body. (not sure of the proper terms) On the other prop which I'm guessing is the Johnson prop (its the same colour as the motor) the body of the prop is straight but there is a groove at the very back which I'm assuming is where the converging ring would snap into. I would only use the Johnson prop as a spare so I don't know if its worthwhile to buy the ring.