I recently bought a new OS max-25LA engine for my planeand it just wont start. I am turning it over by hand as i dont have a starter. When i turn it over it runs for about a second or two and then either locks on the compression stroke or just dies. As far as i can tell the engine should run. The glow plug is fine, the fuel is good and compression is good. I had a 20 year old engine before this and i could never figure out why it ran for a minute the cut out. I thought this new engine would be easy to start.

Any help would be appreciated

Thanks.