RCU Forums - 40 FSR

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- O.S. Engines Support (https://www.rcuniverse.com/forum/o-s-engines-support-133/)

- - 40 FSR (https://www.rcuniverse.com/forum/o-s-engines-support-133/2260668-40-fsr.html)

I aquired a 40 FSR from a friend. I noticed some of the o-ring are worn. I understand parts are not made for this engine anymore. I am looking for the o-rings and gaskets. Are they used in another engine? Also, did OS produce both ringed and ABC type FSR 40s. How can I tell the difference.

If they did make both... what is the best way to brake in a ringed... a ABC?

Thanks

Oh and by the way... the carburator is the 4BK.

Parts specific to the O.S. Max .40 FSR are no longer available from us or from O.S. Max, in Japan. The engine's been out of production for too long. The carburetor o-rings are still used in several engines:

OSMG7388 24981837 O-RING NDL FS/FX/LA $4.49
OSMG7372 24881824 O-RING IV/PRC #6H $2.99

These parts can be ordered through any hobby retailer who sells O.S. Max engines and accessories.

A ringed engine has a piston ring that's visible when you look into the exhaust port of the engine. The ABC-type won't have a ring. The piston is aluminum, the ring is steel, and is dark, when compared to the aluminum of the piston.

Breakin instructions can be found on the O.S. Max web site in the FAQ section.