prop switch between OB to I/O. Johnson to OMC

[Aquaman-PSD]

A friend of mine just purchased an 84' Chris Craft with a 3.8L OMC with a Cobra outdrive. I know that back in the day OMC also made Johnson. I have a Johnson outboard (86') that came with two expensive SS props. My questions is will a prop that is built for a Johnson (OMC built) OB fit on an OMC outdrive? Also a little side question how do you go about finding out what pitch the prop is? I know one of the ones I have is for top end speed and I think the other one is for hole shot but I don't know which one. The one says "Turbo prop" and the other is made by Raker.

 

[steelespike]

Re: prop switch between OB to I/O. Johnson to OMC

According to the prop chart here a 140 or 150 with a V6 gearcase is the same number.
If you look up a prop for the I/O and a prop for the 140/150 V6 gear case Johnsons you can double check the numbers./

 

[Dhadley]

Re: prop switch between OB to I/O. Johnson to OMC

Not really a lot to go on here but here's some food for thought- The 3.8 Cobra came with the V4 style gearcase and also the V6 style. You haven't mentioned what size Johnson you have. Basically if your props are OMC / BRP 15 spline and the Cobra has a 15 spline propshaft they will interchange, assuming (I know - I know) your props do fit on your Johnson outboard (original hubs have not been changed to fit Merc etc). If they are both 13 spline they will interchange also.

The Raker was an OMC 3 blade prop. The Turbo prop was made by Precision Propeller (now owned by Yamaha). The first generation Raker was actually made by Precision but not the second generation or the Raker II. Again assuming the Turbo is a Turbo I 3 blade and has not been reworked it will have as much bite as the first generation Raker and more than the second or third generation Raker. If the Turbo is a Lightning it will have more lift than a Raker. If the Turbo is a 4 blade prop we'd need more info (numbers off prop) to really tell what it is.

 

[Aquaman-PSD]

Re: prop switch between OB to I/O. Johnson to OMC

Wow thanks alot! thats a lot of information! The Johnson I have is a V-6 200hp. I am not sure of the spline, but the I/O motor is said to have170 (actual HP is I think 168) on the title.

On thee props. When you say bite does that mean hole shot or top end. I guess i'm nnot really sure which of the props I should be running. I have the Turbo 3 blade) on there now. The Raker I want to say is a Raker II. Is one better for top end speed and the other is better for tubing and quick planing? This is all very good insight! As you can tell I know nothing about props!

Since we all love pictures here is a picture of my boat and my friends boat! All I have to say is Lets Race!!!!