01 four stroke 70hp not running rite/fuel intake problem?

[nick_0652]

I have an 01 df70. motor will crank up and idle fine, about 50% of the time when you give the motor some throttle it runs great, you can put in reverse, neutral, foward, run the motor stop it turn it back on and its fine, but sometimes when runnging the motor it cuts out almost as if the motor isnt getting any gas. you can pump the bubble to make it run but you have to pump it very tight. once you pump it sometimes it will start running rite but other times it will die as soon as it gets on plane again. I have replaced the fuel line and the fuel pump along with the spark plugs, i dont think that their is anything wrong with the fuel injection because when it runs good it runs really good. I was told that there could be some trash in the fuel vapor seperator and drained it several times, it hasnt helped, i also completly drained the gas tank. I need some help, any comments of suggestions would be appreciated.

[garbageman]

Dealing with a similar thing. Check all lines for leaks. Check filters. There is a screen in the VST on the bottom of the pump. Also put a fuel gauge on top of the fuel rail and run the engine. The pressure should stay constant at around 35 psi regardless on rpm.

[nick_0652]

Thanks, whats the VST?

[Talklessridemore]

VST is vapor seperator tank.
There is a small filter inside of vst. It may get clogged up
How is your primer bulb and anti shyphon valve ?