Also check what voltage your glowstarter is putting out - maybe you are frying the glowplugs. It might last one start, but after the second start you melt it.

Also remember that on the first start the engine is cold, and will tolerate a slightly richer setting. If the engine is warm, and setting too rich, it can just quit when you remove the glow starter.

An engine simply quitting when you remove the glowstarter is often a sign of a mixture too rich because the extra fuel smothers the glow plug, yet with the glowstarter on the glowplug is hot enough to burn the fuel.

But as VORTEXGEN said, can you give more info?