OS 25 Starts Up Nicely then dies and will not start again.

by Keith Finch
(Lula, GA USA)

I have an os 25 max fs. Starts nicely and runs for a few seconds very good. Then when I throttle down it will die and I CANNOT get it to start again. They are finicky little dudes.

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Tuning
by: rcdude07

If you have it tuned proper on the high end, sounds like you need to tune the low end.

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OS .25 FX my perfect nitro motor
by: Anonymous

Is the gas tank too high or too low?

I mounted a .25 fx on a Zero and it only fit upside-down to work with the couling. After many-many attempts to start, run hold vert at wot were all failures upon failures.

I tried starting the whole darn born upside down so the head was up where I prefer anyway because of the glow plug. I wasted a full summer and never quite got that war bird to sing.

Removed it from the model and it fired and ran perfectly on the bench?

Discovery: the tank intake tubes were either too high or too low with the motor mounted properly upside down!

So, I ditched the couling, mounted at wonderful gem of a motor upright and it fired up emmideatly idled, taxid, and took off with no problems ----- except my canter of Gravity was way way off with the motor mounted so high on the frame yet inline with the plumbing?

The tank was unswappable. Added tail weight and it still flew like a short school bus. eventually crashed it but that OS .25 and her two sisters live-on, in a Small Ugly stick and a low wing tweety. Parts are still available and I even have a converted .25 fx for road rally. Cool engines check your tank height in relation to the carb it makes a crazy difference. My 2 cents

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