Glow Engines Discuss RC glow engines

Surging with GMS 47 2-stroke

Old 03-24-2003, 09:16 PM
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Default Surging with GMS 47 2-stroke

I have a GMS 47 2-stroke that has run approx 40 hours.
I recently transfered it from my trainer (where it ran reliably) to a new plane that required it to be inverted.
After an initial few good flights, the engine now surges when the nose is held high and the throttle is opened.
Also it frequently just stops after a minute or two of taxiing around (I wasn't prepared to risk a take-off!).

The only way to stop the engine from surging while held vertical is to richen it significantly - like about 5-6 full turns out.

I have mounted the engine on a bench stand, with the same surging result - so the problem isn't with my fuel supply to the engine.

It seems as though the engine has lost its ability to suck fuel up from the tank - could it be excessively warn already, after just 40 hours?

Any suggestions will be gratefully received as this problem has been driving me up the wall for 2-3 weeks now - and keeping me on the ground instead of up flying!

Old 03-25-2003, 01:02 AM
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Default Engine surging......


I have heard that the GMS engines are prone to air leaks.
that's where I would start looking.


Old 03-25-2003, 03:01 AM
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Default Surging with GMS 47 2-stroke

There is some good information on sealing up GMS engines at

You could also post your question at ... the guys there use quite a few GMS engines.

Hope that helps.
Old 03-25-2003, 01:16 PM
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Default Surging with GMS 47 2-stroke

Hi William,
It could be that your source fuelline is too long, or the fuel tank is too low. Also check to see if you didn't accidentally reversed the fuel lines, this will cause the engine to run when the tank is topped out for a while and die in short order. I hate to mention this, sometimes engines don't like inverted mounting because the fuel gravitate into the glow plug, to remedy this you may have to go with a hotter plug and/or with an idle bar version plug. Hope this helps!


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