Anti siphon valve

[saluscon]

Want to check the anti siphon valve and other lines attached to the gas tank. Do i need to remove the fuel in the tank before i do any work on it? Is there any risk in removing the fitting, sending unit or other hoses while there is fuel in the tank?

Thanks.

 

[dingbat]

Re: Anti siphon valve

No need to remove the fuel. Just don't use a lighter as a flashlight and don't create any sparks.

 

[Silvertip]

Re: Anti siphon valve

Before you start fooling around with the fuel tank, disconnect the NEGATIVE battery cable and tie it up or stuff it somewhere where it connect make contact with the battery terminal. This eliminates the possibility of the boats electrical system causing a spark that would cause a "kaboom". If you know even roughly, how much fuel is in the tank, you don't need to remove the fuel sender to test it. Disconnect the center (normally pink) wire and measure the resistance from the post to ground. Empty tank = 240 ohms, 1/2 tank = 109 ohms, full tank = 33 ohms (all numbers are give or take a bit depending on fuel level).

 

[saluscon]

Re: Anti siphon valve

Thanks guys, big help....

 

[NHGuy]

Re: Anti siphon valve

While you are there check everything. Inspect the hoses for brittleness & cracks.
I have done fuel fill hoses on two boats. We have 4 to 6 month boating seasons around here and they were both older boats. On my current boat there was a crack in the supply hose between the tank & pump. The engine would surge at wide open throttle and wouldn't make all it's power.
When I was doing that hose I just did the fill and vent hoses too cause they too were old. I am with you on checking the anti-siphon. I removed mine and gave it a good bath with carburetor cleaner plus I exercised the spring by moving the check ball with a plastic probe. I didn't see any junk in there, but if there was some it's not there now.

 

[saluscon]

Re: Anti siphon valve

While you are there check everything. Inspect the hoses for brittleness & cracks.
I have done fuel fill hoses on two boats. We have 4 to 6 month boating seasons around here and they were both older boats. On my current boat there was a crack in the supply hose between the tank & pump. The engine would surge at wide open throttle and wouldn't make all it's power.
When I was doing that hose I just did the fill and vent hoses too cause they too were old. I am with you on checking the anti-siphon. I removed mine and gave it a good bath with carburetor cleaner plus I exercised the spring by moving the check ball with a plastic probe. I didn't see any junk in there, but if there was some it's not there now.

Thanks for that advice, i think you may be right, i should just cahnge the hoses and vents to make sure.

 

[seabob4]

Re: Anti siphon valve

If you have an O/B, I'd get rid of that anti-siphon and get a straight thru barb. The springs weaken over5 time and allow the ball in there to close off the barb. $4 at WM...

 

[gdombroski]

Re: Anti siphon valve

If you have an O/B, I'd get rid of that anti-siphon and get a straight thru barb

Don't do this it's a required safety device. When you engine dies, fuel hose problems, whatever, it shuts the fuel flow down to the carb. It's there to prevent big booms. Yes they need to be cleaned or replaced occasionally, but they are only about $15.

 

[seabob4]

Re: Anti siphon valve

Don't do this it's a required safety device. When you engine dies, fuel hose problems, whatever, it shuts the fuel flow down to the carb. It's there to prevent big booms. Yes they need to be cleaned or replaced occasionally, but they are only about $15.

Read the ABYC book lately? They are NOT required on O/Bs, as I stated, only on boats where the fuel inlet to the carb is lower than the pickup, as in I/Bs and I/Os...

 

[gdombroski]

Re: Anti siphon valve

Yes, you are right if tank is below carb/fuel pump but if it has a anti siphon and it is removed it probably needs a manual cutoff valve installed

183.568 - Anti-siphon protection

Each fuel line from the fuel tank to the fuel inlet connection on the carburetor must:

(a) Be above the level of the tank top; or
(b) Have an anti-siphon device or an electrically operated fuel stop valve:

(1) At the tank withdrawal fitting; or
(2) Installed so the line from the fuel tank is above the top of the tank; or

(c) Provided that the fuel tank top is below the level of the carburetor inlet, be metallic fuel lines meeting the construction requirements of Sec. 183.538 or "USCG Type A1" hose, with one or two manual shutoff valves installed as follows:

(1) Directly at the fuel tank connection arranged to be readily accessible for operation from outside the compartment, and
(2) If the length of fuel line from the tank outlet to the engine inlet is greater than 12 feet, a manual shutoff valve shall be installed at the fuel inlet connection to the engine.