old os engine question
 

I have 2 older os 40 engines, one is an os fp 40 and the other is an os 40 sf.
What would be a good starting prop for these engines to get them going?
I got both of them used and have cleaned them. Is there one that is better then the other?

Thanks

Jon

RE: old os engine question
 

I use a 10 X 6 prop on my OS 40 FP engines. Good Luck, Dave

RE: old os engine question
 

the sp is a bushing engine so not as powerful, from what I can find online they are extremely durable. The sf is an abc engine from what I can find online, it is ported a little different but comparable to the newest style engine as far as power.

RE: old os engine question
 

10x5-7 or 11x5 would be good starting points for those engines.

Of the two, the SF is the better one.

Ken

RE: old os engine question
 

Thanks guys, I just got one of them running, it did not seem to transition real well, but I will mess with it some more and run some more fuel thru it.

Thanks

Jon

RE: old os engine question
 

Those are both good motors, 10-6 is a good starting point for both, 40fp will take some breaking in and will need to be run a bit rich untill broken in or it will overheat and quit. The 40 sf will keep up with any modern .40 and run really well.

RE: old os engine question
 

Which one did you get running? Remember the FP's are bleeder carbs and the mid range screw (the horizontal one near the front of the carb and that tiny hole directly in front) works opposite of the double needle types such as the SF. The midrange is leaned by unscrewing that screw and the mixtured is enriched by screwing it in.

John