Ok Norm ,if you are using the side pull full crank motor and the coils test ok they should be good enough, I would just check anything you may have missed to make the engine start easier as you know these usually start easily especially after the engine has run and is warm.
You could just make a list of things that could go wrong and check them.
The muffler could have restricted flow.
I've had ports that are half closed off by bad castings ,I don't know how they got through QC as the motor lost a lot of power.
The decomp can be removed and blocked off by a spark plug to check a difference in starting if the decomp is closing too slow.
It's worth double checking everything as sometimes I've seen a piston in backwards.
Use a carby from a mower that you know works well.
Also seen crank cases that are warped and leak.
A non genuine thickness lower barrel gasket can throw the port timing out.
Another thing I would do is check a good 24 mower that starts easy with the comp tester on one pull start cold and if the rebuilt motor doesn't have at least as good a psi reading there must be a problem.
I've also seen damaged leaking crank cases ,one example is when someone has used a wrong bolt that's too long and broken the crankcase like the starter main bolt on the side starter.
One good thing about putting a spark plug in the decomp hole is you can spin the motor over and hear leaking compression from a warped head or from somewhere else.
Also sometimes I check the keyway in the crank is cut in the correct location and check the flywheel key slot is in the correct location to the magnets as machining can be slightly out sometimes.
Check the mounting position of the coil in case of casting shift or drilled slightly out and that the coil wasn't fitted incorrectly.
It sounds like a bit of a head scratch if you've already checked most things.
