Thanks Alton, now we are getting there. Here is your Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/iorvDKJU0HCjhJvcv4.pdf

Here is your Illustrated Parts List:
http://bsintek.basco.com/BriggsDocumentDisplay/18kvuCXNnfBhU7y.pdf

I suggest you download this manual - it is free, and is the official Briggs overhaul manual for all the single cylinder Intek engines:
http://www.ccdist.com/_serviceManuals/briggs/276781.pdf

Your engine is referred to as the 310000 throughout: you can find all the specific references to your engine just by searching for that number in Acrobat. Here is an illustration of your compression release, from page 140 of 179, in the manual:

[Linked Image]

You can see that there is a piece of stamped sheet metal attached to the camshaft, and pivoted so that when the engine is rotating very slowly (cranking), the stamped piece is edge-on beside the cam, and projects so that it stands up slightly higher than the cam. As the cam rotates, the edge of the piece of metal strikes the cam follower and lifts it up until the stamped piece has rotated far enough to be past the cam follower. This is the decompressor action: the exhaust valve is bumped open momentarily about halfway through the compression stroke, so the compression process has to start again for the second half of the stroke, and only a relatively low pressure is developed in the cylinder: about 80 psi. When the engine starts running, a centrifugal weight moves and allows the piece of stamped metal to pivot out of the way, so the exhaust valve is not bumped open during the compression stroke, and the full compression pressure of about 150 psi develops in the cylinder.

The problem is that the stamped metal does not stick up very far above the camshaft, so if the exhaust valve has slightly more clearance than it should have, the valve will not be bumped open at all, and the starter motor will be trying to crank the engine against a compression pressure of 150 psi. It will fail at that task, and if you keep trying, it will burn out. Note that the edge of a piece of stamped metal is not a very durable object, so after a time, it wears down and the decompressor doesn't work anyway.

So, it is critically important that you set the valve clearances precisely accurately. Now, if you go to page 175 of 179 in the manual, you will see that for the 310000 engine series, the required valve clearance is 0.003-0.005" for the intake valve, and 0.005-0.007" for the exhaust valve. Please check the actual clearances you have, very carefully with the engine cold, and report back. You should be aware that the problem you have is a very well known one, and a lot of servicemen set both intake and exhaust clearances to 0.004". I do not recommend that, since it is below the minimum specified clearance for the exhaust valve, and could in theory result in a burned valve. However given the very common problem with decompressors, it is easy to understand why they do what they do.