I gotta prime my mower like 100 times to get to to turn over. I got new gas, it's not flooded, I'm not smelling lots of gas on the prime, the plunger is in good shape. It just doesn't "sound" like gas is entering the carb. Instead of hearing "squish" on the prime I'm only hearing "Pish" of air.

 

After 100 primes and 50 pulls it finally starts. Once it's warm it starts first pull after that.

 

What would cause a carb to not prime. ?

Is there a hole in the primer bulb? It doesn't have to be very large.

Is there a hole in the primer bulb? It doesn't have to be very large.

+1 this. Probably a pinhole. You can get a new bulb for a couple of bucks. Youtube to see how to replace. Nothing to it.

 

Unless a line is clogged. While you are at it, replace these too. Also cheap, nothing to it.

Try priming with the gas cap loose or off.

Sometimes the vent in the cap gets so clogged it causes a vapor lock

in the tank and the bulb isnt strong enough to suck the gas in

Ditto with above posts. Other than that hit it with one shot of starting fluid. If it starts right up thats probably your problem. Its always good to store a can of starting fluid. Works on all motors. And bees.

There is a small line between the primer bulb and the carb.  Many times the line splits/cracks where it attaches to the carb.

The bulb is new replaced it like two years ago. I like the idea of the gas cap off.

 

Are there any other "seals" I need to check? Like do all carb gaskets need to be fine for a good vacuum to happen on the prime? Oris the prime just a pure squirt to the carb?

There is a small line between the primer bulb and the carb.  Many times the line splits/cracks where it attaches to the carb.

This^^^^.    Over time this hose gets brittle and develops cracks.  $2 fix.

The use of Ethanol in gas can deteriorate the plastic bulb & gas lines

and left over gas can form a shelac type residue inside gas lines

 

Always good to end the season by adding Stabil fuel additive (I prefer Marine Grade "Blue" myself)

and run the engine out of fuel so no gas remains in the lines to break them down while stored.......

Startron here.

IMHO way better than Stabil