So, I think I destroyed my fuel pump

[barmanvarn]

Apologies for the long post....

Late last year I decided to start work on my '69 C15 that had been sitting for around 10 years. It took a lot of work (and a lot of help from the forum) but I finally got her running. (No brakes, so she's not going anywhere. Was just happy to get the engine to run). I haven't worked on it since early spring so this weekend I decided to do some maintenance before winter hits.

One item on my list was a fuel tank. Obviously the stock tank is toast so I've been running a line to a portable gas can just as a temporary measure. I was wanting to set up something so that I wouldn't have to haul out a gas can every time I need to run the engine. I settled on an outboard fuel tank that I could sit in the bed of the truck. This way my Dad (the truck is behind his shop) could go out and start it every once in a while so it doesn't go downhill again.

Anyways I hooked up the new tank, filled it with gas and Stabil and tried to start the engine but it wouldn't crank. I pulled the fuel line off the tank to check for pressure in the line, but when I remove the line from the tank, gas came gushing out of the tank. I then checked for pressure in the line and got nothing. Even checked the input line at the pump and still got nothing. At this point I'm pretty sure the pump is toast.

After some research, I think I found that this marine tank doesn't have a manual vent but has some kind of automatic one. The gas gushing out when I removed the line tells me the tank was pressurized meaning the pump was trying to suck out gas from the tank but was unable to since there either is no vent or the vent isn't working. I'm thinking this put too much stress on the pump and basically ruined the pump.

Does this sound about right to you guys?

I'm going to replace the pump (which is obviously toast) but I guess I need to figure out what went wrong w/ the gas tank. Again, I"m guessing it's a venting issue but wanted to see what you guys think.

EDIT: I did some more research on the fuel tank I'm using and am a bit confused. It appears to not have a manual vent (due to new EPA regs). It has what they are calling an "automatic vacuum valve" in the gas cap. What confuses me is that it appears to release pressure when the tank expands, but I'm not seeing any way that air gets in when the pump is trying to suck out gas, thus the issue that I encountered.