Purney,

Your compression check might show one reading that is quite a bit different from the others. This will indicate problems with that cylinder. You could possibly have a blown head gasket, cylinder to cylinder without involving the water jacket.

The strange thing here is that the engine starts and runs for a few seconds. Do a search in this forum on 'compression test'. You will find info on the proper way to do it and what the results might indicate. Have you checked the timing and verified the wire position/firing order.

If a intake valve is hanging open or is burnt to a crisp, when that cylinder tries to fire it usually blows a fireball back through the carburetor. The compression test will be a good starting point to troubleshoot this problem some more.

Stuart