gregoryshock

I've been a proud owner of O.S. Engines since 1996. I have two identical 61 FX Engines, one is only a year old. Both O-Rings on the Needle Holdern failed at that the beginning of the flight season. I have been wondering if something in the fuel could be causing these O-Rings to go bad. I have always used OMEGA 10% or 15% nitro by Morgan Fuels, and I have never had an O.S. O-Ring go bad before. (I used to fly with 15% Nitro, and Now I fly with 10%) The O.S. Manual says do not inject after-run oil into the carburetor. I have faithfully followed steps stated in the O.S. manual.

Link to Morgan Fuel:
http://morganfuel.com

* The O-Rings became brittle and broke.

Bax

My Feedback: (11)

Here are the stock numbers and list prices of the parts you asked about:

OSMG7370 21281800 O-RING I VLV 6 8H7L7M US$3.29

Since the part is almost an external part, exposure to the elements and other contaminants may have been the cause, but it's not possible to tell. The fuel should not be a cause.

Lamoilleriver

Have OS engines over 20 years old and never an o-ring problem, most recent OS engines have had needle valve o-ring problems. quality control is lacking some where in the system. Put pressure on the o-ring supplier.

smh20502

My Feedback: (1)

o-rings like fuel tubing will fail. It's not a matter of if but when. I suggest getting the dimensions, durometer and getting a few to keep on hand.