Anti cavitation ring questions

64osby

Admiral
Joined
Jul 28, 2009
Messages
6,799
I took a prop in to have it fixed, 13 x 19 Alum. from an Evinrude 135Hp 1974. Prop came with the motor I bought last fall.

The service tech looked at the prop and stated it was missing the anti cavitation ring, and there is no ridge to hold one on even if I wanted it.

Questions are - How important is the ring?
What adverse effects can there be from not having the ring?
Should I look to get a new prop and keep this as a spare?

He also stated some people don't like to have them and ask for them to be removed.

Any input is welcome.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Anti cavitation ring questions

On some set ups you will see some venting, on some you won't. Some props don't have them, some do. A pic of the prop will tell us if it ever had one. We'd almost assume an aluminum prop had one.
 

Frank Acampora

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Jan 19, 2007
Messages
12,004
Re: Anti cavitation ring questions

Depends upon the design of the prop. Some have the ring, some don't. Some have a flare at the rear of the hub, some are straight. So: Is it important? Were you having a running problem? If your prop was designed with it, yes it is important. If there is no ridge to mount it, then the prop was not designed for it and no, it is not important.

I think you need to see a different service tech. Spouting off about what you do and don't have is not always in the customer's best interest. Sometimes it just causes more needless worry.
 

64osby

Admiral
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Jul 28, 2009
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Re: Anti cavitation ring questions

Here are some pics.

I think these guys are pretty good, 2 welds, clean it up, balance it and paint $36.00. I have used them before.

I have never had the motor on the water. Bought it in the fall for my project boat that needs a new transom.
 

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etracer68

Ensign
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Oct 11, 2009
Messages
906
Re: Anti cavitation ring questions

Keep it as a spare, and get a new one for use.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Anti cavitation ring questions

Yes, it was produced with one. Time and testing will tell if it needs one on your set up.
 

64osby

Admiral
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Jul 28, 2009
Messages
6,799
Re: Anti cavitation ring questions

A different prop the tech showed me had a lip or flare on the hub to hold the ring on. How would the ring be held on - or how would the lip or flare not be there, if it had one?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Anti cavitation ring questions

On that prop it's pressed on but they're not a real tight press fit. Not unusual for them to be off. The lip or flare is the defusser ring. Try it like it is. As mentioned, some props are noot produced with them.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Anti cavitation ring questions

If you look at the prop there is a groove in the hub. That's what holds the diffuser ring on. The prop came with one. Sometimes that ring cracks and it falls off. Some run just fine without it, other setups may require it as was pointed out.
 

64osby

Admiral
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Jul 28, 2009
Messages
6,799
Re: Anti cavitation ring questions

I really appreciate the input from you guys.

At this point I will leave it alone and try to run it as is and see what happens, All I need is a new transom and ice free water and I'll test it out.
 
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