1991 200 yamaha outboard

[chaston6]

having a problem with out board motor when running for about 20 mins it starts to suck the ball in and motor cuts out like is starving for gas. I turn it off for a few mins, pump the ball and it will run for a little while.

[axolotl98]

Check the tank vent.
Seems to be blocked by something

[shallowmindedguy]

Gas supply

I agree sound like tank vent, pinched gas line, or even the pump bulb. My typical solution to to totally eliminate the gas tank line etc. with seperate tank system then start eliminating the exhisting system piece by piece.

OH, some boats have gas tanks with anti spill check valves that will stick and cause you lots of headaches.

Good luck