mercury 6hp, 2 stroke. I have had the gas tank, line, and bulb replaced . Engine cuts off after 2 min. Why ?

clean carb and adj.float and valve

Fuel starrvation to carb ? or blocked filter / diapraghm in carb ?

overheating. or too rich a mixture will be causing soot on the spark plug preventing ignition.

if it just dies out and then when you pump the bulb you can get it to run for another 2 minutes, it sounds like the fuel pump has gone bad on the engine. If there is no pump, then the carburetor jets might be clogged enough to keep fuel from flowing.

Not to state the obvious but make sure the vent on the tank is open.

fuel flow prob, too much/little 2 stroke, iffy carb. spray wd40 directly into float chamber wait 20 secs then run engine.

when it cuts off is the primer bulb still firm?

is the gas tank vent open and clear?

when it shuts off, will it start back up again easily?

most likely, worn carb float valve needle/seat flooding the engine. carb rebuild will fix it.

fuel pump has gone bad on the engine. If there is no pump, then the carburetor jets might be clogged enough to keep fuel from flowing.

Not sure as to your ignition system, but look for condensor replacement in system. Cheap to replace but hard to test. They normally brake down in use after the same amount of time and then will allow restart of engine when they have cooled down. If not this look at coil.