Identifying old SS OMC prop size

[gilera]

I have 4 SS props that came with various parts engines I have bought. They are 13 spline for mid 70's V4 OMC motors - all were between 73-77 models 85hp or 115hp.

I cannot see any markings anywhere on these and cannot find much on the internet about the options that were available for pitch at the time. There appears to be no markings on them. Can anyone give advice on how to work this out ?

 

[southkogs]

Do you mean outboards? I don't think splines matter much on the Stringers through '77. I thought those all used a pin and cotter key.

 

[gilera]

Do you mean outboards? I don't think splines matter much on the Stringers through '77. I thought those all used a pin and cotter key.

Sorry didn't mean to confuse by saying OMC. Yes they are Evinrude/Johnson outboards - standard 3 blade props that use nut with cotter pin and backing plate. I'm just wondering whether there were different pitches for the blades. The diameter is same for them all. Seems strange not to have various options for pitch to suit different applications and strange there seems to be no markings on them.

 

[southkogs]

No worries: I actually thought I was reading in the OMC forum as opposed to props anyway ... so who's confused ?

I had a couple of props for my old Sterndrive that weren't marked well (one wasn't at all). There aren't any numbers inside the hub area at all? I'm pretty sure there were optional pitches and diameters; We had an old 65HP that we had a couple of prop options on hand.

 

[racerone]

They were available in 15 , 17 ,19 ,21 and 23"pitch.----And I am sure they are marked with or a part number.

 

[gilera]

They were available in 15 , 17 ,19 ,21 and 23"pitch.----And I am sure they are marked with or a part number.

Ok thanks. If there are markings on them then i cant find them. If i know exactly where i need to look i can use a bit of metal polish to check carefully.

 

[Scott Danforth]

IIRC, they were stamped on the hub near the splines

 

[gilera]

IIRC, they were stamped on the hub near the splines

You were right thanks.

 

[gilera]

Hard to make out on one but it looks like 13-3/8 x 17, 13-3/8 x 17, 13 x 19 from what i can make out from these three. I'll check the others tonight.

 

[Texasmark]

I bought an OMC SST in 1973, their first sales year, for my 1972 new 18' tri-hull, bow rider, Caravelle with a 125 Johnson. I wanted a prop that I could use on Sunday and not have it in the shop on Monday with a bent blade and the price I paid was $185 plus Texas sales tax.

I clearly remember it was a 13+ x 17 and would run the boat at 39 with me only...didn't have a tach so I had no RPM reference....remember that I could never get it to 40 and wasn't about to change props. On a company picnic occasion, I was able to get 5 skiers up for about 200 yards before one fell off and ended the experiment...most were on 2 skis and light weight persons. I couldn't believe it....but it is true. It was an unusual very cool September day and too cool really to be playing with water sports....but we did it anyway.

 

[racerone]

See they are marked.----Have a bunch myself.----17 , 19 , 21 ,23" pitch.

 

[Scott Danforth]

I used to run these on the 400 stringer. would buy them off of craigslist for $20-$25 because they were not shiny and the fad was shiny props.... great props

 

[jimmbo]

Here is a page from the OMC Accessory Catalog

 

[gilera]

Here is a page from the OMC Accessory Catalog

Thanks for posting that - very helpful to have somewhere to start!

 

[jimmbo]

I can't remember what year that was from, probably early 80s. Some of the Part #s have been superseded, and there have been newer designs since then.
At least OMC offered a large choice of Props for the post 68 V4s, for most of the pre 69 V4s, only 3 were offered.