Small Engine Troubleshooting Problems? Ask a Mechanic Now.
The hose should have a pulse, not vacuum, as the pulse is the piston moving up and down in the cylinder. displacing the air in the crankcase. If you have fuel pump hooked up and line off the carburetor, do you get any fuel flowing when cranking? Do you have compression?
Do you feel the pulse? Will the pump work if you use test line from the fuel pump inlet into a fuel container? May be time to check compression!
The pump suction side has to be vacuum tight, that is why you need to use a test line and eliminate everything else. Will engine run if you put gas direct into the carburetor? You can add a low pressure electric fuel pump if need be.