How important is the diffuser ring on the prop?

[happyfast79]

I have a 1975 Johnson 15 hp tiller on my 16 ft crest liner and the diffuser ring on the end of the hub on the prop cracked and fell off, will this effect much? It will be used mostly for trolling but may use it as a lower fuel consumptions option to cruise the lake.

 

[boobie]

Run it, should be all right.

 

[flyingscott]

I run my 30 hp without one works just fine.

 

[jimmbo]

We lost the one on our 1980 35hp, never noticed any difference

 

[racerone]

These rings look nice.----Perhaps part of getting around patent issues.-----Remember that this was 1968 when diffuser rings were first installed !!!

 

[F_R]

Yep, Evinrude invented the first thru-hub prop, but never really marketed it. But Mercury did. I'm sure it was a patent gimmick, but I'm not a lawyer.

 

[jimmbo]

Merc had a Outward Flare on their 'Jet Props'. It might have been Patented separately. OMC had their ring which would divert water into the low pressure area behind the prop. Later OMC installed the same Ring backwards on the V6 props. And then there are the all the SS props that are just a straight tube, no flare or ring...