motor surging

[jddens]

I have twin mercrusier 350's, 330HP each with throttle body injection. My port motor recently developed a surging problem. Giving it throttle from idle and it wants to die then takes off and will surge from 2000rpm to 1000rpm at part throttle. My first thought was to replace the water separator and fuel filter...no change. With the spark arrestor off I can see the spray pattern increasing and decreasing as the motor surges....this motor has an electric fuel pump. My current thought is that the fuel pump or regulator(assuming it has one) is the problem. Am I on the right track? Any suggestions? Thanks in advance for your help.......John

 

[deadstick]

Re: motor surging

if you think it is your fuel presure, i would use a fuel pressure gauge to check it before, i replaced any thing.

also, have you tried a simple tune up. wires, plugs, dist. cap and roter button. your spray in your throttle body may be surging be cause of a skip in your engine.

 

[180shabah]

Re: motor surging

It's fuel injected, you have a pressure regulator, it is integral to the throttle body.

As mentioned above, test first, then replace.

Is the 330hp correct? computer reflashed to match?