OS Max 90 2-stroke
 

What do you know about this engine? Good reputation/bad reputation? It's older but it looks to be in good shape. Also, whats with the 'back mounting plate'? I'm thinking of buying it from a buddy and using it in my nearly completed TF Corsair.

Thanks for you input.

Scott.

RE: OS Max 90 2-stroke
 

Your picture appears to be an OS 90 FSR with the 7 D carburetor, If indeed it is good shape it is a wonderful find. These where top of the line at there time and still a powerhouse by most standards. The back plate mount is an aftermarket, if I remember correctly it was made by foremost co.



Just my $0.02 worth

Don//

RE: OS Max 90 2-stroke
 

Thanks Don,

The 7 D has not only the high and low but a midrange adjustment also - is that correct? I'll check this engine to make sure and if it's as good as the pic I'll purchase it.

Scott.

RE: OS Max 90 2-stroke
 

No....the 7D just has the two regular adjustments. ;)

FBD.

RE: OS Max 90 2-stroke
 

Put a new rear bearing in it, unless the original is perfect, and it will run forever. The one I ran for years had only one quirk, it would not break into a rich fourcycle without an idlebar plug.

RE: OS Max 90 2-stroke
 

Thanks for the input all,

I purchased the engine and the bearings seem to be in excellent shape - in fact, by the looks of it, the engine has actually never been run (if it has, only once to see if it starts)! There is no castor build up anywhere and the piston doesn't have a mark on it.

In order for this engine to fit I'll need a Pitts-style muffler. Anyone know where I can find one for this old engine?

Thanks again,

Scott.

RE: OS Max 90 2-stroke
 

Nice find on the engine. As noted by others....... its a very good engine.

Its going in a Corsair huh....... hmmmmm.......
check with the usual bisson and slimline folks ... they may still have bolt-on style mufflers for the FSR series. Tatone and Jtec use to make pitts mufflers for it back in the day.

The Jett turbo-jett incowl muffler is available with the appropriate adapter if you wish to try one of those.

I cant open the photo, I think I have one the samm which I bought some years ago. Started it today but the needles are different than usual. How can I see the photos?

There is only one photo from 11 years ago and it is already open, it only enlarges a little.