New engine was running fine for 7 flights.
After that it was stored along with the plane for about 4 months with no activity.
Now upon resuming the activity, engine is very hard to start and does not hold idle.
After idle stables, after 30-40 sec engine stops.

Plug = OSF new
Feul = High performace Heli 30% nitro
Prop = APC 17x12 Wide
Header and Tune are Hatori 821 and 822

Please advise.
Amram Leshed

The engine could easily be full of corrosion or be completely gummed up in four months time. It needs to be taken apart and inspected for rust and debris, and cleaned thoroughly.