I just picked up a old but never run O.S. 1.20FS 4-stroke engine. I am pretty sure this is a pre-surpass engine. It just says 1.20 FS on the side of the engine. Also, the valve cover is two individual covers instead of the usual O.S. single cover. What is the difference between my engine and the surpass? Is my engine still a good, reliable, strong engine?

Thanks,
Tony

Your engine will run very nicely. However, it will not have the same peak RPM level as the FS-120 Surpass (with or without the pump) series. It should run in the mid-to-high-8,000's when propped with a 15 x 8 prop or so. The RPM will vary considerably, depending upon the brand of propeller.

If it needs parts, you'll have to scrounge for them. O.S. has not had parts for that engine for about two decades.

Bill,
Thanks for the info. Do you know if my engine and the new Surpass have the same mounting dimensions?

Tony

Bill,
Do you think an APC 15X8 or APC 16X7 and a 14oz. tank will be a good combo for this engine?

Thanks,
Tony

Those props should work OK. Look for power output in the 8,000's.