O.S. Needle-valve replacement

Jun 23, 2011 2 Comments by


With regards to the O.S. pumper engines, I have the original series O.S. 120 surpass with pump and c12 carb. this engine was recently involved in a dispute with the ground about 40 yards from the runway, and well, the plane lost the argument. But the engine survived, kind of. The needle broke off along with the threaded portion where it goes into the carb body, Believe it or not, this engine, pump included, ran like a dream with loads of power. I was wondering if you can point me in the right direction for a replacement carb that works with the 120 pumper? Or maybe a fix? I absolutely love the way this ran and this is the only issue after the crash, so any ideas would be much appreciated!

Have you tried Hobby Services that service the O.S. engines for a needle valve assembly?  (2170398-0007. If they can’t help I’m sure Gary Conley, who now makes the Perry carburetors would have one that will fit.  (630) 858-3199.

Clarence Lee

Clarence Lee, Editors Blogs

About the author

Executive editor About me: I’m a publishing professional who has a passion for aviation and RC, and I love creating issues, books and a website that help RC pilots to enjoy this sport even more. I admire scale aircraft and enjoy the convenience of flying smaller electrics.

2 Responses to “O.S. Needle-valve replacement”

  1. Raymond Johanson says:

    I have a NIB OS Surpass 1.20 w/pump as you described. I bought it new in 1987 (or so) and now plan to use it (I’m slow, and just retired). I remember a plumbing fix in RCM which included a tee fitting or two to reduce pressure to the carb, does anyone remember the details? How can a person submit a question to Clarence Lee?

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