boat stalls after 30 minutes of running

[rcraig77]

Problem:
Boat sputters then stalls after ~30 min of running, amount of time is regardless of speed
This has happened ~10 times

What I've done:
drained water seperating fuel filter while on water, was able to start and idle home, sometimes had to drain multiple times, every time it will start and idle.
Drained gas tank ( it WAS treated over winter)
Added fresh gas and ran through ~25 gallons
replaced filter 4 times, drained reused dried out filters ~15 times

My thoughts:
water was in tank somehow, hence draining filter allows boat to restart and run for a short period.

My Concerns:
With adding all the new fuel, after draining old, and running so often periodically draining filter why would there still be water in fuel system? ( I did add HEET multiple times) Could I be getting water in fuel system while under power?

I appreciate any thoughts at all on this matter, I am out of ideas!
Thanks, Ryan

[seapuppy]

nope...sounds like the vent is plugged...run the boat till it stops...then go to your tank inlet cap...remove it...if you hear a hiss...there's the problem.....the engine is drawing the air out of the tank and the vent isn't allowing air to be replaced....thus the engine stalls and can't draw any gas into the carb....


SP

[oneradride]

Exactly! You beat me to it! Used to happen on my smaller outboard with the primer bulb set up and the tanks you could lift out. (The good old days) The tank had a vent and if you forgot to twist it open, you were dead in about 10 minutes. The suction of fuel leaving creates a condition called cavitation and the fuel pump can’t overcome it because with fuel exiting something needs to come back in (air). Twist it open, prime it again and off you go. I know the Maxum’s vent is not clogged because if you get it to full it sprays out everywhere from there……. Good advice Seapuppy, thats where I would start looking. Good luck!!