Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Anti Siphon Device

Posted by wrangler on 10/02/15 - 4:43 AM
#1

1979 Montauk 90 hp Yamaha 4 stroke
USCG (CFR) regs requirement this anti siphon device to be installed on the withdrawal connection on the top of gasoline fuel tanks. It is used in case of a fuel line leak and it prevents the siphoning of the gas from the tank into the boat.
My 20 gallon Moeller tank had it installed. It is 4 years old. The engine stopped running after 2 hours 1 day.

The anti siphon device (about $20.) got stuck closed and no fuel was able to be pumped from the tank. It is male threaded 2" long with a barbed end to attach the fuel hose. Inside is a small ball and spring. The ball fits against a seat. It clogged up and the ball froze closed while the engine was running.

This needs to be checked as it happened to me all of a sudden. You can disconnect the fuel hose and shove it into the fuel tank through the fill cap to get back to the dock as an emergency means.

Posted by Finnegan on 10/02/15 - 9:52 AM
#2

Mercury warns against the use of anti-siphon devices, and says they can kill outboard engines! On any above deck tank, or belly tank, they are DEFINITELY not needed, since the primer bulb serves the same purpose. Whaler never installed them either - not on my Outrage 18, 19 or 25, all with internal fuel tanks.

If you have one on your Montauk tank, remove it.