Fuel Delivery

[jrhalling]

We have a 1991 Sea Ray Sundancer 420/440 with twin 7.4L gas engines. We are having trouble getting fuel delivery from the port side tank. I have already checked and or replaced all of the inline filters and have disassembled all of the fuel directional manifolds to make sure that they are routing and functioning properly. We have also replaced the fuel pump on the port side engine. When we switch the port side engine to the port side tank it will run for just a while with the fuel that is remaining ing the carburetor and fuel line and then just quit. Once we switch back to running the port engine from the starboard tank then it runs fine. Any Ideas ? Thanks :smt100

 

[Happy Hour IV]

antisiphon valve stuck, air leak between tank and and valve manifold, clogged vent or problem with pickup tube in tank

 

[jrhalling]

Hi HH IV,
Thank you very much for the suggestions; I will check them out this weekend. Just a quick question. Where is the "vent" located? I believe that the antisiphon valve is in the fitting at the top of the tank; is that correct?
Thanks,
JRH

 

[Happy Hour IV]

antisiphon is usually at top of tank. Hard to recognize it as anything other than a brass fitting. just look for one extra piece of hardware.

vent will usually go from the top of tank to a little vent fitting on the side of the boat below the location of the fill fitting. I kind of doubt that it is a clogged vent based on how quickly the engine shuts down. However if the tank is close to full there is not much air space to slow down the onsite of a vacuum developing.

 

[Happy Hour IV]

One other thought, do you have flow meters? Mine are installed after the valve manifold so if one is clogged the engine shuts down no matter which tank it is on. If they are installed before the valve manifold the engines cannot run on the tank with a clogged sensor.

It does not take much to clog one of these especially if any teflon tape had been used in the line ahead of a sensor.

 

[twyant]

Had this problem last week turned out to be a cracked flare fitting on the fuel line at the manifold motor was sucking air and because it was a suction line it did not leak fuel