mercury efi failure problem?? please help suggestions needed

[Gerry Zagorski]

If they are thinking it's a fuel issue easiest way to find out is to hook your motor up directly to a portable tank.... If that does not resolve your issue you know everything on the boat is likley OK. If it does resolve the issue then keep on working backwards from the motor introducing more of your fuel delivery system inline with the portable tank. Put it just before the primer ball, then the filter, then the line coming out of your boat fuel tank until you get the same issue and you have found your culprit.

If it turns out the issue is in the tank, the check valve PA Fire mentioned is a usual suspect. One other thing to before that would be your fuel vent line. If it's clogged it can also restrick the flow of fuel. Easiest way to check if the vent is clogged is to simply open your fuel cap which allows your tank to vent and try and run the boat...

Good luck. Frustrating stuff but using the protable tank will help you from replacing uneeded parts.