OS lower W/different powerhead

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topfuel443

Well-Known Member
Vendor
Joined
Oct 23, 2002
Messages
6,451
Has anyone out there used the OS lower unit with another powerhead???? ??? Like the k&B with a CMB or Nova Rossi/Rossi. Ive run the stock OS for two seasons without the first problem or cable breaking. I hear evryone talking about K&B flex shafts breaking, why not use OS. Is there any engine that will work :-

Im sure the OS lower is more expensive, but if its better, it makes sense.

~ James
 
James,

I've never seen anyone attach a different powerhead to an O.S. Max 21 lower unit. The most obvious reason is the mounting face for the O.S. lower unit does not match any other motor.

I supose some type of adaptor plate could be made. But, then you'd need to have special cables made becase the adaptor plate would create a space between the lower unit and the power head.

If you've never broken a cable on an OS OB, you've sure had better luck than me. I have broken a few OS cables.

Jerry D.
 
I have been running an OS for three years now and I am still on the same shaft. I run at least twelve sanctioned races a year with it plus test time so it gets a lot of use. If I could get the piston and liner to last as long as the drive cable it would be a winner. I have also looked at converting it to a different power head and I think it could be done but you would have to machine a new PTO housing to make it happen. Jerry, I don't know what you are using to lube the shaft but here is what I am doing. I use a Lawless shaft and instead of using the muffler to lube it I just put a piece of fuel tubing at the top inlet and bottom inlet and shoot STP into it between races. The first shaft I got from OS lasted one run using the muffler lubrication system.
 
Hi there,

Maybe we can get the idea of converting Nova Rossi inboard to outboard by changing its crankshaft. Thus, we can get the existing OS .21 engine, e.g. RZ-M, VZ-M which is much powerful then the existing power head will be a easier solution.

Have a good day. ;D
 
osracer, I do the same thing with the cable lube. I have a hose going from the original inlet for the muffler luberto the lower inlet. I use the hose as a fill tube to lube the cable. Although I used the muffler lube system for about a year with no problems, and still use the same cable that came with the engine without a hitch.

I think with the OS mounting plate being Big you could mount another power head to it by making new holes if need be ..... just gottat find a different powerhead now to try it with ................MAC???? ;D ;D
 

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