40 hp stalls

[Capt. Rich]

Hello All, My 2004 40hp 2 stroke Merc has been flawless. I run ethanol free fuel with Marvel Mystery Oil, and Techron Fuel conditioner. All of a sudden my 13ft. Whaler can't get up on plane. I nurse her home and then the engine idles like crap and stalls out. I replaced the fuel pump, all fuel lines including the tank to engine lines. I took off the carb and inspected. It looked new with no sludge or corrosion. I cleand it even more with carb cleaner. Re-installed and she still runs like crap. Starts right up with the key depressed energizing the primer solenoid. Runs for about 30 seconds and then stalls out. What else could it be?

 

[stork55]

You did'nt say what your running for a fuel tank,I assume it's a portable tank.Take your cap loose and see if it will run(venting problem).Also check your fuel line connector at the motor,may have a bad oring and it's sucking air instead of fuel.Don't forget the basics,spark and compression.