[Ender]

Low compression is a likely culprit. If gas blows past the seals much it'll wash out the oil needed to seal the chambers, and then it'll just crank and crank because it can't build compression. This is a very common problem with low compression rotaries. A temporary fix sometimes works, you can install a fuel cut switch so it doesn't just POUR fuel into the chambers on startup. You probably will have to rebuild a motor with that low of compression before soon though. I would keep that in mind. My TII came to me with probably 80psi compression and had the same trouble starting and I used a fuel cut switch to help it start. I was probably lucky to get ~8,000 miles out of it before it let go. I knew it was coming though and I had stocked up on all the parts I needed for a rebuild, so when it died I was prepared to build myself a new, better motor.