I'm having a strange idle problem with my Evolution 26. If I set the idle speed to get a good idle the engine will die when throttling down from high rpms. If I raise the idle speed high enough so that it doesn't die, when i throttle up and down it will idle at a low rpm for about 5 seconds then the rpms increase about 1000 rpms. I've tried adjusting the needles, both high and low, and it doesn't change. I've taken from sloppy rich to die in transition lean with no improvement. Throttle servo is fine as is the linkage. I cleaned the fuel screen in the carb and pull the needles and cleaned. the carb was clean inside.
Anybody have any ideas?
James

I had the same problem with a 3w 55i.....it got better with breakin.

This motor has more than 50 flights on it and this problem has been getting worse lately.

bump

sound 2 me you may have a leak in the crankcase or possibly in the reeds (if these engines have em) and dont forget the dreaded crank seals.start it and idle it rough,use a pump sprayer to spray water at and along any seals. if you hear a change that will bee your leak,or blow some smoke into carb and look for leaks that way(only works for smokers)you will need to position the piston to cover the ports though.no leaks,goog carb leaves ignition problem.

Homrich,
thanks for the suggestions, I'll check again for leaks. I went ahead and put a rebuild kit in the carb and that improved it some but it still isn't right. I ran two tanks of fuel through it last night trying different tuning and throttle setups. If I set the low end extra rich it acts better. If I pull it from full throttle to idle it goes to a low idle speed but if I ease it down then it goes to a high idle. I don't think the linkage is binding but I'm going to absolutely eliminate that possibility next.
james

Do you use a lever extension on the throttle arm at the carb?
Like the one on the right?