ef2000isV2 will not stay idling in eco mode

[bigTvik]

I bought a ed2000isV2 last year for ice fishing. it only has about 20hrs or run time on it. iv changed the oil and verified the oil level, replaced the spark plug, cleaned the spark arrestor,cleaned the air filter, verified the fuel cap is venting properly. when i put it in eco mode it will run fine for the first 10 mon. then when idling it will run great and then just fall on its face like you turned to on/off switch off. it won’t die but comes very close. it will do that about every 3 minutes about 5 times. then eventually completely dying. starts right back up and runs fine. iv tried pulling the choke out when it starts stumbling and it has no effect. it does not appear to be a fuel issue. any thoughts or advice

[CycleRob]

bigTvik,
 You do not say whether you use a fuel stabilizer additive, Ethanol gasoline or how long the fuel has been in the tank.
 It still could be the fuel, as in bad or waterlogged Ethanol fuel finally making it to the carb floatbowl. Always try the easy shots first:
1-- Try draining the carb floatbowl to empty, then turn the fuel valve turned on to flush out any potentially fowl liquid remaining.
2-- With the engine off (DUH!!) be sure the throttle stop is fully touching the full throttle limiter lug.
3-- Drain and refill the gas tank with fuel from a different fuel station, then repeat just step 1 again.

4-- If those steps have no change, replace the spark plug with the recommended NGK brand.

5--Last of all and more difficult, check the 2 carburetor mounting nuts for tightness.

Beyond that, the symptoms could be a weak spark and the ignition coil and pulse generator will need to be tested.