Merc 40 stalls

[strombolichef]

0G369283 SN. 96 Mariner 40 hp30jet. The engine is new to me call so it is no longer a jet it's been converted to a prop Drive. What I've done, checked compression 118 to 120 on all cylinders, replaced water pump and gear oil, replaced water separator cartridge and inline fuel filter, got new gas and run the engine for about a half hour with seafoam in the gas. Also I replace the spark plugs with new ones copper the ones that are flat on the ends.
what's happening is the engine will start if I choke it then it'll run good with the throttle up a little bit and then if I pull it back to idle it will slow down and idle for about two or three minutes and then die. Then when I try to start it again it won't start unless I choke it even when it's been running for a long time.
I pulled off the gas line and turned over the engine using the starter and observed gas coming out of the fuel pump
for some reason I've noticed that the inline filter is never completely full.
I've also noticed that it takes me about 20 or 30 hard pumps on the priming bulb to fill the system till it feels firm and then after the engine runs the priming bulb feel soft again and never feels firm without being pumped a bunch more times.
I have a Mercury dealer near me and can do most work by myself. So I can get parts.
what I would like to know is any advice about how to get the engine so that it runs continuously without shutting off and stalling thank you for your advice

 

[Mercurylips]

So many fuel problems. Start by changing your fuel line from the tank to the motor and include a new bulb. Then take a look and replace any seals or o rings that are leaking air and or causing a lack of fuel supplied to the carbs. (open the air vent on the tank) If opening the vent cures your problem then you have a spare fuel line which all of us need. If you can pump the bulb and keep your motor running, you may need to rebuild your fuel pump. You should get your parts here. Good pricing.