Check Valve to prevent Vapor Lock

[04select200]

Has anyone installed one of these? I have been experiencing vapor lock and tried idling and running blower, but I am still having issues.

I purchased the check valve today and it goes between the cool fuel cell and the thermostat. I have a 2004 5.0 MPI and I know the thermostat is on top of the center of the motor by the intake manifold, but I do question where the cool fuel cell is. Is it on the bottum left by the fuel filter / water seperator? My boat is about 150 miles away and I don't have internet connection other than my phone. I need to make sure I know exactly where it goes.

 

[fc3]

Check valves don't prevent vapor lock. Some boats use an anti-siphon valve to prevent fuel from siphoning from the tank, but that's another issue. The downside of a check valve is that it adds a restriction to fuel flow and there is a pressure drop across the check valve. The pressure drop is inherent in the physics of a check valve. Because you are adding a restriction and pressure drop to the fuel system, you are making it more likely that the engine will vapor lock. You can add the check valve between the fuel pump and the fuel rail, however ABYC, NMMA, and Coast Guard regs require that this pressurize line from the pump be a metal line. You may not use rubber hose or insert a non-metal check valve in this circuit.

Best regards,
Frank

 

[Dave S]

If Frank is correct in his reply then I agree with it. But I think you are talking about a valve for the water intake line rather than the fuel line aren't you?

Since you mentioned "Cool Fuel", I don't know if I have an answer for you or not but here is a picture I took of my 350MAG a few years ago when it was pulled to fix an oil leak and it shows the water lines for the Cool Fuel unit.

The two smaller lines you see above the red hose are the water lines that go into the cool fuel unit on a Gen3 Cool Fuel. To the lower right of the picture you can see the intake connection for the water pump as well. I don't know if you have the same set up as I do but in this case I don't think an anti-siphon valve is necessary. The water cooling lines are so far away from where water enters the block itself I don't think heat soak of the fuel cooler is a problem (which is what I think you are trying to prevent correct?)

The older style coolers like the one I had on my 1999 210 Suindeck were subject to heat soak and an anti-siphon valve did help a repetitve vapor lock problem I had with it. I did have had vapor lock with my 260DA one time with the Gen3. It was at the beginning of spring and the dealer felt it might have had something to do with winter blend gasoline (I boat year round). If you did not experience vapor lock in seasons past then maybe the gasoline blend itself is a plausible explanation.

Dave

 

[04select200]

The check valve goes in the water line between the fuel cooler and the thermostat. That is what is says in the instructions. I think I can figure out when I get to my boat later this week, I just want to make sure I have a good idea. I am a mechanic by no means, I can change water pumps, and alternaters........about enought to get my self in trouble if you know what I mean.

 

[rkeats]

I started using Sta-bil Ethanol treatment in my boat and the vapor lock issue went away. Ethanol has a lower boiling point then gas, so that is why it is happening more then in years past. More ethanol in the gas. Give it a try.
Good luck

 

[04select200]

Perfect, will do.