My Evo 26 has a problem I can't figure out. It will run fine for 3 to 5 minutes. Good high end, good idle. Then it will begin to go vroom, vroom, vroom , vroom vroom vroom until it finally quits. No bubbles in the gas line. Sounds like a car engine with bad plugs or points. Has a electronic Ignition. Could the electronic ignition be bad. Any idea's Thanks Stuka Jon

Maybe it's overheating?! I just took a shot in the dark. At what throttle setting does it go, "vroom, vroom?"

Wideopen throttle. Will even start doing the vroom, vroom when it is set rich on the needle. No cowl so plenty of air for cooling. Stuka Jon

Sure sounds like an ignition problem. Mine used to do that when the ignition battery was getting low. The Evo's ignition is very sensitive to voltage dropoff. What battery are you running, if I can ask?

Battery 4.8 700 mah When I check the battery with a meter it has almost a full charge. Evolution recommended the 4.8 battery with the instructions. Stuka Jon

Jon,
it seems that you have the older version of the ignition.
does it sais "4.8V" in blue on it?

if so, these ignitions are very sensitive and it might be malfunction.
i had one of these ignition that burnt.
eventually i changed the entire engine to GT2 with the new ignition module.

on one of my gas engines (DZY 26cc) i had a similar problem, the engine didnt hold a full throttle for more than half a second and was sound exactly as you described.
i found out that one of the DC capacitors (internal component) of the ignition module broke off - probably due to vibration.

When your checking your battery, are you putting it under a load? What kind of battery are you using? NICD, NIMH? I don't know off hand what the max amp load is from the gen 1 ignition, but I do know that I have the same engine, and had the same problems your describing, till I switched to a larger battery. It's especially telling when you say it happens at WOT. That's when the battery will see the largest amp load and if the battery is too small to support the load, the voltage will start dropping.

Please keep us updated as to your findings.

Jon - I keep telling you to switch to electric! Hurricane Larry

All you Evo 26 owners If you are having difficulty with you Evo 26 as I was (see above ) all you have to do is replace the ignition with a CH and trouble is gone. With the new CH Ignition it runs better then it ever has. Lower idle, higher top end, easy starts and no vroom vroom vroom as before. As I stated above the CH ignition unit is over $100 cheaper the Horizon Hobby. Bye Bye Horizon when you diliberatly try to rape me I'm gone Stuka Jon

Glad you fixed it!

buy a new engine John