Does your engine have normal compression without the DDD head in place, but with the stock head? If it doesn't, that is one of the problems you have to fix first. Fix the compression problem first. Then buy a new batch of fuel from DDD and mix that up.

Old model diesel fuel is bad news. Like you said, you can smell it with the can sealed. If you can smell it, the ether is evaporating. You NEED the ether to get the engine started reliably and to run correctly. I know that you attempted to address this problem by adding starting fluid ether. If the ether leaked out, chances are the aromatics contained in the kerosene did too. You need fresh fuel.

Keep the fuel tank at the proper height. That is, the centerline of the fuel tank should be no more than 3/8ths of an inch below the level of the carburetor jet (spray bar). It should never be above the level of the spray bar. Centered is perfect.

Proper prop selection is a big help too. I'll assume you are running a larger prop than you would with the glow head in place.

First things first. Get the compression taken care of. **** has OS.40FP engines up for auction all of the time. It may be less expensive to buy a used engine in good condition than to replace the piston and sleeve of your engine with new parts. Do your homework.

Good luck and report back as to your progress.

Ed Cregger