Fuel Valve

[HorizonHunter]

I have a mechanical question. I have two valves between my fuel tank and my motor. I have an Atomic4. I like to shut off both valves and then let the engine run out of gas and die. I do this to try to prevent a very slight gravity fed fuel leak from the carburetor.

My question is: Is shutting the fuel valves while the engine is running bad for the fuel pump? I know it creates a suction or vacuum in the fuel line, because when I go to open the valve you can hear it relieve the pressure. Is this bad for the fuel pump? I was thinking that it may put a heavy load on the internal diaphragm in the fuel pump.

[tommays]

having a manual valve is a good thing BUT

There should be BY LAW and anti-siphon valve on the fuel tank which takes care of forgetting to move a manual valve and any failure of the fuel line while running


I just put a rebuild kit in my A4 fuel pump and carb and am glad i did as the pump would have leaked very soon

[HorizonHunter]

hey Tommays,

so the check/Anti-siphon only lets fuel flow in one direction, and will only allow fuel to pass through when its being pulled by a pump or some force.

I am going to install a check/anti-siphon valve.

Was it very difficult to set the air/fuel mix once you rebuilt your carb?

[HorizonHunter]

you think something like this would be fine

Horizon Hobby: Check/Anti-siphon Valve by Sullivan Products (SUL756)

[klem]

It is almost always best to fix the real problem which in this case would be the carb. You are doing some damage to your fuel pump with your current method but probably not too much. Most fuel pumps are lubricated by the fuel and actually do not seal all that well. It sounds like your fuel system is tight since you say that you can hear vaccum in the system when you open the valve so you don't have the problem of air. However, you are forcing the pump not to seal well because of the negative pressure which is not good for it.

[tommays]

You need to get a marine one that threads into the fuel tank for 5/16 fuel line unless you not A4 standard not much money 10 dollars


And you should be using A-1 marine fuel line

[Leither]

To answer the question, it won't do the pump any harm since it is a flexible diaphragm type and therefore requires no lubrication.

However, I agree with others about sorting the source of the problem.

Stuart

[HorizonHunter]

Thanks for all the tips. I am going to install the marine check valve. I am also going to take off the carb and pump and service them. Its on the 'to do' list with about 100 other things.

[slevbag]

thanks for the tips. In the wee hours, I found another source online.
EsgDirect.com.Phone 716 578-8449. This convinces me what a great resource SailNet can be