Small Engines (Lawn Mowers, etc.): Tecumseh carburetor problem., correct compression, float bowl

Question

carb I just acquired a MTD 15.5hp mower that won’t start. The  engine is a Tecumseh OHV155-204509F.  Engine Family: YTPXS.4902AA
It isn’t getting gas into the carburetor.  The air filter is clean.  Everything in the carburetor looked clean but to be sure, I cleaned everything inside with carburetor cleaner. Gas is getting into the float bowl and I have checked everything inside the float bowl. I did replace the o-ring on the main jet. All the ports are clean and open, float is ok, it has the right level of gas, the anti-backfire solenoid is working and everything in the carburetor is clean and working, but still no gas in the chamber.
It has good spark. The engine will run for a couple of seconds when I spray gas into the carburetor.  I don’t know what the compression is supposed to be but it when I tested it, it was 90psi.  When I put a little oil into the cylinder, it was 110psi and then started to drop back to 90psi.  
1. What is the correct compression?
2. So that I can understand, can you explain the process of how the gas is pulled into the carburetor from the float bowl?


Answer
I see you have a pump on the side,I bet that it is not working correctly? Your compression is good,If it runs when you spray gas into it than the pump is not allowing gas flow? Make sure that all wires are hooked up and that it is working.You can try jumping the pump to a hot wire and it will work for you to see if thats the problem.Best of luck,
Jason