You should be able to get it to run in a brief burst after priming through the exhaust ports.

It sounds as if either the fuel-pickup tube has fallen off the nipple on the back of the tank or the very fine hole that feeds the venturi is blocked.

I assume this is a Baby-bee-type engine with the built in aluminum tank?

If so, remove the tank and check that you can blow air through the fuel-pickup pipe and that it comes out the venturi

Also check the needle-valve to make sure that the very tip hasn't broken off and lodged in the fuel jet.

Other than that, I suggest you ask your question over in the 1/2A forum where there's a wealth of experienc with these little engines and everyone is very friendly.