Replacement Prop?

[BQMatt]

Hi All-<br /><br />I may not be giving enough info for you to answer my question, but I'll ask anyway. Maybe you folks can point me in the right direction.<br /><br />I have a 1979 Cobalt 18DV with the Mercruiser 888 outdrive. Engine is a 351. <br /><br />The prop I have now is pretty beat up, and I am looking for a replacement. I'm not necessarily looking for a performance increase, though if it matters, I would prefer top end speed rather than hole shot performance.<br /><br />The problem is that I have no idea what size and pitch prop I am currently running. I cannot find any markings on the prop to indicate what it is. Maybe I'm just looking in the wrong place?<br /><br />I have seen many posts indictating that I need to know what RPM I am turning at WOT before I can choose a prop. Is this true?<br /><br />My boat is on the trailer right now, and is in a convenient location for me to work on it. I plan on putting it back in the marina early next month, where it is harder to work on, so I'd like to replace the prop before then if possible. Also, I can't really run it to get the RPMs until I get it back to the lake. Or can I? Is this something you could do on the muffs? It seems like it's a bad idea to me, but I'm just learning, so what do I know?!<br /><br />Anyway, any help or pointing me in the right direction is much appreciated. Thanks in advance!

 

[WillyBWright]

Re: Replacement Prop?

There should be some numbers on the hub, either at the propnut end if it's a Merc prop or on the thrust washer end if you have a Michigan Wheel. Do you recall what your RPMs were at top speed before? Otherwise you're probably safest getting a matching pitch. You need a proper load to know what you need, so don't try it on muffs. Your current prop may be rebuildable.

 

[BQMatt]

Re: Replacement Prop?

Hey thanks for the reply! I looked again and still cannot find any markings anywhere on the hub. I'm not familiar with the terms propnut or thrust washer, but I examined the hub as thoroughly as I could with the prop still mounted. Do you have any further tips?<br /><br />As far as needing a proper load, duh! I knew there was a reason that it would not work on muffs. My brain just couldn't put 2 and 2 together when I was thinking it over I guess! Either that, or I wasn't putting enough thought into it! Thanks for setting me straight.<br /><br />I don't recall the WOT RPMs from last season, so I guess I just need to get her back out on the water and see where I'm at, unless you have any other suggestions. <br /><br />As far as rebuilding my current prop, is there a price range that that usually runs? I'm not even sure what it's made of. The previous owner of the boat painted it, but most of the paint on the blades has worn off. It doesn't really look like SS or aluminum, but if I had to guess, it looks more like steel than alum.<br /><br />Thank you for the advice! I'll be checking back in when I have more useful info.

 

[Bondo]

Re: Replacement Prop?

Take the 1,1/16th" Nut Off,+ Look Behind it......<br /><br />The Size should be stamped There........<br /><br />Rebuilding Props runs about $60.00 around here at the local Prop Shops......

 

[BQMatt]

Re: Replacement Prop?

I'll check that out. Thanks!