My 9.8 mercury is still not pumping gas properly. The compression is 120 on both cylinders, I put a new pump kit (gaskets and new diaphram), new bulb and hoses, new pulsator line and new plugs late last year. The first time I ran it this year it was a few weeks ago with last years gas that had seafoam in it and it ran perfectly. A week later on my way to the lake I put 3 gallons of new gas and oil to the can that had 3 gallons in it already and it hasnt run right ever since. I am afraid to use seafoam because a mechanic said it can ruin my diaphram. And is it possible that there is an obsruction between the fuel pump and carb. Also if the two check valves go bad in the fuel pump would it cause it not to pump gas through the motor, and how can I tell if they are bad. I am running out of things to try. Please help!!!!!!!!!!!!!!!