If you have been trying to start this thing for months I strongly suggest you pull the plugs and give a couple of shots of oil down the cylinders before going further.

It may be just lack of compression after starting/flooding many times. If nothing else, this can't hurt. And, don't worry about the oil fouling the plugs, it will be fine.

Does it pop at all? If it does, the above may be enough to get you going.

Good luck to you.