Basic prop question - 1970 Merc 500

[MartyTn]

I've been looking for a NOS prop with correct pitch for my Merc 500 on my fishing boat. Recently I found one but this prop is missing the ring that normally is on the rear of the prop hub. According to charts, with this prop I should be able to turn at or near max recommended RPM at WOT, with speed approx 27'ish mph. So, without this ring, am I just losing a little performance, or are there other more serious considerations?<br /><br />Thanks to all,<br /> Marty

 

[Laddies]

Re: Basic prop question - 1970 Merc 500

just a little preformance you should be able to buy the ring at a prop shop or dealer, a little epoxy and your in business--Bob

 

[achris]

Re: Basic prop question - 1970 Merc 500

Marty,<br /><br />There is one more thing to consider. That ring also stops exhaust gases getting back into the blade area, so you could run into some ventilation problems. As Bob suggests, buy a new ring, glue it on.<br /><br />Chris....

 

[MartyTn]

Re: Basic prop question - 1970 Merc 500

Thanks guys, I have sent a note to the prop shop inquiring about the ring. I believe I had heard at one time about issues in higher speed turns, and ventilation problems would seem to fit right in with that scenario. I noticed that many of the earlier smaller HP motors with thru-hub exhaust didn't have the ring, so would the lack of speed capability on the smaller motors possibly explain why some had the ring and some didn't?<br /><br />Many thanks,<br /> Marty