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Remote needle valves in os .50 SX and .91 FX

Old 09-28-2003, 05:16 PM
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Default Remote needle valves in os .50 SX and .91 FX

This is a posting in the general "Glow" engines section. There are many people complaining about the problems experienced with the remote needle valve in several OS engines. Bubbles form between the needle valve assembly and the carburetor. A OS .46 FX with a different type of remote needle valve does NOT have the problem.
I request an answer and a solution from OS or representative in the US>

I am using (correction, was...) the OS .50 SX, which uses the same remote needle valve as the .91 FX.
Same problems as described above, the most puzzling aspect is that the bubles generate between the needle valve and the carburetor. So, the logical conclusion is that either the o-ring in the needle valve or the white gaskets in both sides of the nipple are at fault. Added a little lenght of fuelt tubing to the needle to seal the entrance to the housing. Not solved.
Changed the gaskets, same problem... the engine hesitates, surges and slows down, and then runs OK. The hesitations and surges are usually after idling down, in flying terms when you are at the end of your taxing and about to take off. Very, very unsettling.
I have ordered new o-rings, not received yet but I suspect the problem will still be there.
There are two other spots where the bubbles may get in: the intake nipple before the needle and the intake nipple in the carburetor, both fitted with the same white gaskets (smaller, of course) than the nipple.
I made the test of running with an external tank and the results were inconclusive. Besides, is VERY evident that the bubbles form between the needle valve and the carburetor, not before (tank to needle valve), as many ground runs have proven to me.
Now, is OS taking any action on this. I'll repeat this problem in the manufacturers forum and I'll not want a wishy-washy answer. From there to the Japan site of OS is just a mouse click away.
Old 09-29-2003, 01:46 AM
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Default RE: Remote needle valves in os .50 SX and .91 FX

Sorry to say this, but I had to install a Perry carb on my .61 to get the engine back to the OS standards that I'm used to. In my opinion, I understand the remote needle concept, but think the technology is way behind the performance. It's a shame that society has dictated such things, but hey, when you have to put some of the off the wall warnings that we see on end user products you have to ask yourself if we don't deserve it? Personally, I don't need to be reminded not to use my blow dryer in the bathtub[X(]

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