hello. im putting a question out to all the evolution engine enthusiasts. im having a problem with my new 100nx. im trying to get this tuned, and here is whats happening. at idle, not bad. transition, not too bad. now, if i leave at full throttle for a minute and return to idle, the engine stalls out and i have no compression until it cools down. also, if i leave it at half throttle, the engine will stall. i tried to fly it tonight, and took off with no problems, i backed off the throttle to about half, and the engine stalled. none of the guys at the field have any experience with evo engines, this is my second one, i have a 61nx, and it runs well, but i didnt get it new. it had about 5 tanks of fuel through it. any help on this would be very appreciated. oh, this engine was purchased brand new, and at this point, i have about one tank through it.

Usually when an ABC engine looses compression it's because it got too hot and the sleeve has expanded. Compression comes back when cool. You give no mention of what fuel, plug and prop you are running.

Yes, it sounds like it is simply overheating at full throttle....

update. i got the idle steady and the engine doesnt heat up like it used to. I turned the low needle rich. also, the mid is a little better, but still stalls out. I learned that if i adjust the high speed needle lean the mid throttle stabilizes quite well, but its too lean at wide open throttle. im attaching a video take a look and tell me what you think. Thanks. http://youtu.be/hldxRTYLWwU

You need to adjust the low speed needle so that you just barely notice a drop in rpm when the glow driver is removed. The high speed should be adjusted to max rpm and backed off about 1/8 turn. The needles will influence one another to a degree so you will have to tweak each one a couple times.

Typical 2-needle carbs need to have the main needle set first because it's in a fixed seat. I usually recommend what Hobbsy does and to peak the main needle and leave it peaked then get the idle needle set. Once it's idling & throttling right, set the main needle richer. Using a hot plug in those Evolutions is said to be highly recommended.

Im hoping the glow plug is hot enough. Its the one that came with the engine.

Blw has said many times the stock plugs aren't hot enough. Try a hotter plug, you might be surprised.

What would be a good plug to use? I was using a #6 in my 61, but that's not long enough, and they kept burning out. Then I was told to use a type F, and that seems to work just fine in my 61. Any other suggestions?

if you have an issue with ANY plugs burning out quickly it's because the engine is being run too lean and/or you're using too much nitro.

+1 on the lean mixture and/or too much nitro burning plugs.

I refuse use to use OS plugs. I use McCoy and Enya plugs; MC59 and #3 respectively. A few guys here really like Merlin plugs, Dub Jett sends Merlin plugs in his engines so they must be good.

dont think its running lean, but not ruling it out, and im running 10% sig champion fuel. thanks for the recommendations. ill look at getting a hotter plug for my 100.

10% nitro is not too much nitro for that engine. Burning a plug means it's too lean or overcompressed. If you haven't removed a head shim to lower the head then it's too lean.

Too lean. It's not the plugs fault as they are the right heat range. The reach doesn't matter here. F's are too cold. If you are running that lean be sure to have castor in the fuel as other parts are getting punished like the glow plugs.

The F seems fine because the mixture is too lean. Once you get the mixture richer you may see where the F isn't burning all of the fuel and it runs too wet. You may notice it only when the engine is cold after you first crank it.

Anyway, that's been my experience with Evolutions.

Among glow engines, the Evolution 1.00 NX and the GMS 1.20 2-strokes are considered two of the great mysteries of the universe. I have no helpful advice to offer, but desire to simply wish you good luck.

I have a evo 100....runs great. I use a 13- 8 master airscrew prop and 15 percent s&w fuel. Don 't run the motor over 9,000 with this prop or it 's to lean.....tach it each flight.

Still working the kinks out of mine but it runs much better than it did a week ago. Think I just need more run time on it

Glad to here that. Keep at it.i was just giving you an idea of what the motor can do. I thought I could wind it to. 10,000 or And found out, not with that prop after 3or so dead sticks on my extra 260 . Good luck.....RON

Evolutions tend to be a little more like the old Tower 75 than an OS, though nowhere near the extreme of the Tower engine. They need a running time to break in. The parts are tight fitting and the chrome is hard.

update on my evo 100nx. after two weeks and a gallon of fuel, i got frustrated. but one thing i did notice was almost every time i primed the engine, as soon as i took my finger off the carb, i would notice the fuel in the line would immediately start flowing back to the fuel tank. i checked and the tank sits level to the carb. at this point, we figured that i had an air leak somewhere. i pulled the fuel tank, put a new one in, all new plumbing, tore apart the carb, cleaned everything out, new fuel lines, sealed the carb as ive heard there were problems with the seals on them. sealed the exhaust. took it out yesterday and set it really rich, got it started, tuned it rich and decided it was now or never. it was going home a whole plane, or in a garbage bag. it flew great! a full flight, no stalls. sounded great! checked temp and i could put my hand on it and not burn myself. i dont know what part fixed it, but i fully think it was sealing the carb. let me tell you, when i fine tune this, and get a bigger prob, this engine is going to be a beast!! i hope this helps anyone else that has an evo.

This happens to all makes of engines. Otherwise, we would all be having too much fun. I always suspected the wives were behind gremlins like these.