Yes, it sounds like the contrapiston is too far down. Fit of the contrapiston is a tricky thing. Too tight and it will not move back up after being pushed down. Too loose and it leaks. I'd suggest you push the contrapiston up until it touches the screw screwed partway in. Before you start flipping, turn the prop over by hand to be sure the contrapiston isn't too far in. Choke the engine a couple of times, finger over the intake, and start flipping. If it does not fire after a half dozen flips, turn the screw in maybe 1/8 turn. Again turn the prop over to see that it is not hydraulic locked. Flip another half dozen times. Keep this up until it fires. If it bites you it is overcompressed and flooded. If the prop just ocellates back and forth, it is overcompressed. Diesels flood easier than glows and do not like to start flooded.

Once the engine starts you will probably need to back the compression off a little at a time. If the engine is overcompressed, it will heat up and slow down, with black exhaust. If it is undercompressed it will misfire and the exhaust will be clear. Run your engine undercompressed a little the first few runs. If the needle is too lean, the engine will misfire and die. If too rich, it will have very oily exhaust and act overcompressed. Run it a little rich the first few runs.

Jim