I pick up one these for my low wing trainer and so far it's been a pain in the rear. Problem is it starts up and runs for abit then dies, it then may start back up or may not. I done all the normal checks for this and follow the tips I found here but still the same thing. I have this mounted in a Tower Hobbies Voyager 40 MKII and for now the engine is mounted right side up. Thanks for any help.

Hi Melkus, I have a GMS 47 and haven't had any problem with it.
Do your self a favour and check all your fuel lines for kinks,then check to see if your clunk is not caught in the top of your tank or even fallen off,which sometimes happens.
Then if all thats ok we need to know what have you done with the settings,have you played with the low end needle ???
It should run at about 2 turns out from closed on the high speed needle for start up then turn it in approx 1/2 a turn to reach near peak revs. Thats if you havent touched the low end needle.
If you have let me know and I will tell you how to adjust it correctly.
Also do you have a good glow plug in it ?? I use an OS F type plug in all my 2 stroke motors with great success.
Hope this helps.. Joe

Thanks Joe for the reply. Fuels lines look fine, no kinks etc, fuel clunk in tank is still connected and swings freely. Glow plug is what came with the engine so would say it's OK. I have the High speed set by what the book calls for 1 1/2 turns, I have mess with Low side and can't say for sure what the factory setting was[:-] but can check it when I get home. One thing is that when the engine dies out there is fuel in the line at the carb, can pull it off and fuel comes out of it.

Melkus,

I recently went through a similar problem with my new GMS 47. I had screwed with the needles and wasn't sure what to do. After seeking advice from my mentor (45+ years in the hobby) he gave me some good advice. To get it running, I started with 3 1/2 turns out from closed on the high speed needle and 3 1/4 turns out from tight on the idle needle (this was the factory setting on another new GMS 47 I had yet to touch. From there, I would start the plane, move to full throttle and have someone pick the plane up and point it nose up. It would start to sputter and die so I would qucikly move it back to idel to keep it running and I would turn it 1/4 turn rich. I did that untill it wouldn't die when we picked it nose up.

Hope this helps,

Ryan

G'day Melkus,
Here's the same settings I have on my GMS 47. But remember I am at near sea levell, so they can differ if you are at a higher altitude so some fine tuning might be required.
High speed needle 1+ 7/8 turns out from closed and the Low end needle is at 1+ 3/4 turns out from closed.
I also run 10% nitro with coolpower not castor.
Good luck ..

My GMS 47 had been deadsticking and generaly just not running well like yours until I got some high temp silicon gasket maker and sealed the carb and backplate with it. It now runs great. Try this it might help
Karter

I have a GMS .47 engine that I've had good and bad luck with. When it was new, it broke in quickly and ran great for the whole season. While it sat in my garage over the winter, however, the cylinder head bolts worked loose and I didn't notice it until I was at the field trying to start it and I noticed fuel leaking out of the head. I couldn't get the old gasket to reseal properly, so I ordered a new head gasket set and cylinder head to replace the old ones that wouldn't seal, and I had some trouble getting it running again.

I decided to replace the glow plug with an O.S. #8, and I got the engine runnining reliably again. I decided to run a couple of tanks through it on the ground just to make sure everything was going smoothly again. Just about the time I was convinced that my GMS .47 was good as new, the drive shaft broke while I was running in the engine on the ground. I sent it in to Hobby Services along with my receipt from Tower Hobbies, and they shipped me a brand new replacement.

Some of this may be pertinent to your problems, some of it may not be pertinent:

1) My engine doesn't have a remote needle valve. If yours does, try bypassing the remote valve.

2) My cylinder head bolts worked loose. Make sure your cylinder head and backplate bolts are completely tight. Check for fuel leaks at these spots.

3) If you start out with a top-notch glow plug like an O.S. #8, it rules out one more variable while you're troubleshooting. Spend $6 and buy one.

4) I'm normally a stickler when it comes to thoroughly checking your tank and plumbing, sounds like you've done that already.

When a GMS engine is running well, it's a thing of beauty. Hopefully you can get yours sorted out and enjoy flying it soon.

Thanks all for the help but still no dice on getting this to act right. I should have pointed out from the start that this was a new engine which Im trying to break it and this cutting off after so long and hard to start back up not helping. I kind of whis I spend abit more and got another Evolution 46 NT which I have on my Sig LT-40 right now and it runs great in fact I never had to adjust it at all. I will keep messing with this one but don't count out me not getting something eles to try