Help with DLE 61 issue
 

Have a peculiar issue with a DLE 61 and need help in identifying the cause
The engine has fair running time and was bought preowned. Worked and flew fine for few flights and then started acting up.
It would instantly pop on choke. With choke off would just run to burn the prime. Choke again and it repeats the same results.
Partial choke the engine runs but obviously would not reach peak.
Tried adjusting the needles, cleaning the carb filter, flushing the carb, checking the tank and lines, changed plug but to no avail.

Next step - Changed the carb to a brand new one from VVRC

Ran fine for may be two runs and the problem returned
Checked all the above again, reeds look to be well seated, no cracks or visible damage on the reeds, plates, gaskets or the reed block
At wits end trying to diagnose the issue so that it could be fixed.

Any help is appreciated

Does the engine have normal compression both before a run and after? The symptoms you describe could be caused by a stuck ring. Looking in the exhaust port, how clean is the ring land area and skirt on the piston? Another possibility of the cylinder base gasket being bad or the cylinder just not being tight. It might be a good idea to remove the cylinder to inspect the piston, rings, ring gap, etc. and replace the base gasket in the process. Any oil residue along the crankcase parting line? That area could be a source or problems. The engine might just be worn out and need rebuilding.

The case and head parting line does not have any signs of leak. After doing all the above mentioned carb fault finding I too was gravitating towards a worn fit in the cylinder that is not able to create enough low pressure in the case to draw in the mixture when the carb is fully open.
Replacement parts have already been ordered.

Any other pointers?