mower was "surging" when it ran initially ( would rev to full throttle then drop to sound like it was on choke. did this over and over again at a set rate)

I have seen this before on other mowers, and I changed the carburetor and any gaskets in disrepair and that fixed the problem.

I did the same thing with this mower. New carb and replaced a ripped gasket. BUT, now the mower will not start at all.

Any input would be greatly appreciated.

Thanks,
Chris