Anti Siphon valve question

[guinnessmeister]

Hello all - I have a 2000 Glastron GX185 - Volvo 4.3 - Carbureted w/Holley 4bbl - I am chasing a lean condition/carb backfire at initial acceleration (runs fine after that at all rpms). As part of the troubleshooting I pulled the anti-siphon valve and noticed that there was essentially no fuel in the fuel line (had the boat out a week ago). The anti-siphon valve looked clean and was operable but I did notice that when I put carb cleaner in the hose end of the valve that it would slowly trickle back through the valve. The questions... 1) Is it unusual that there was no fuel in the line? 2) Could this be an indication of another issue, maybe fuel pump not working? 3) Should the anti-siphon valve completely block any flowback? (this would explain why no fuel was in line) Thanks a million for any help

 

[Don S]

Re: Anti Siphon valve question

The anti siphon valve is there for one purpose and one purpose only. To prevent fuel from siphoning out of the tank if a line breaks below the fuel level. It will prevent a siphon.
It is not there as a back flow preventer for the fuel pump. That is done in the fuel pump.
If you are looking for a cause of a lean condition, you really need to follow these procedures to test your boats fuel system.

http://forums.iboats.com/showthread.php?t=283269