Quote:
What the heck is an antisiphon valve and where would it be?
Boat Manufacturers are required by law to install an anti-syphon valve in the boats fuel system. The valve is usually a hose barb fitting with a checkball and spring inside. It is usually mounted to the fuel tanks pickup tube where the rubber fuel line attaches. Some anti-syphon valves are mounted to the fuel filter assembly on the outlet side.
The purpose of the anti-syphon valve is to prevent fuel from syphoning into the boats bilge in the event of a break in the fuel line.
The problem is that the checkball inside the valve gets worn and tends to jam thus restricting the flow of fuel
The symptoms of a bad anti-syphon valve are, hard starting, surging RPM's while under way, hesitation or backfiring upon acceleration and lack of wide open throttle (WOT) RPM's
I am pretty sure you are on to something here. I have been chasing a problem prior to this not getting WOT RPMS and now I know what part you are referring to. There is one on my water seperator housing where the fuel from the tank hooks up. I would have never thought of taking it off and looking at it though. This will be my next thing to inspect. The only symptom I did have though was the lack of being able to obtain WOT RPMS. Thanks for the info. If this turns out to be the problem I owe you big time cuz that should be an easy fix. Any idea where to get a new one? Is it a common found marine part? Gonna do some searching when I get a minute.