IŽam trying to revive an old OS .35 engine to put on a trainer.
After disassenbly and cleaning, the engine went to the trainer, and fired up quickly, The trouble is every time I pull the glo starter the engine stops. Is it the glow plug?

Why don't you try another plug and find out? If a new plug doesn't fix it, odds are you are too rich on the low end.

Which OS35 is it? If it's got a cast iron piston and you're using normal RC fuel then you're lucky the engine won't keep running

If the compression feels OK then you've either got a bad plug, bad fuel, or the mixture is way out. Is it cutting out at idle or full throttle?

Just a thought, but if it's the older baffled piston type, is the piston in the right way round? Is the liner in the right way?

Thanks for the input guys, it was a mix of foul plug, and carburator setting.