fuel pump

[chevyfan420]

My recently purchased 79 Chev came hooked up to propane, and I'm going to switch back to good ole' gasoline. I pulled the existing fuel pump off to put a new one on. when i got it off, it had 3 fittings on the bottom. one goes to the tank, one goes to the carb....so where does the 3rd one go? it is a nipple type fitting and has a small hole in the end. It blows when the pump is used. does go to the charcol canisiter?

[phantom dually]

one is a fuel line inlet, the other is a return or a vent, and the other goes to the carb.

[Mike76251]

The third line (return) was designed to circulate gas through the system to prevent vapor lock. It works pretty good until you get a load of California gas in the summer. Not much will prevent that crap from changing state as it is so "light".

[chevyfan420]

so i can run an ordinary fuel pump that has one feed and one return?

[RodKnockin]

you can just plug that one off just take the nipple off, and put a plug in it, if its removable. I plugged many of the off in the past witha small piece of hose and a blocked plug just use real hose clamps, instead of the sqeeze type.

[crackajacka]

yea i did that but i have to leave my gas caps loose so the pressure doesnt build up and blow some hoses off lol.... anyone know of a way to fix that btw? not tryin to hajack the post or anything just wondering

[mike reeh]

Originally posted by Mike76251
The third line (return) was designed to circulate gas through the system to prevent vapor lock. It works pretty good until you get a load of California gas in the summer. Not much will prevent that crap from changing state as it is so "light".

Been running "california gas" for years and never had a vapor lock problem even in the mountains.

Chevyfan: got any details on how that propane system was setup? Sounds interesting...

crackajacka: I bet your vent is plugged in your sending unit. Dont ask me how or why but it happened to me.. I ended up drilling it out for temporary use until I replaced the sending units.. It only happened to one of my tanks, too.. BUT that was with my entire fuel system setup and working like stock, even the charcoal canister.. If someone 86'd your canister, they may have plugged the vent at the sending unit.. If thats the case, you'll be building pressure. If I were you, I would start at the sending units and trace the vent lines up to the engine compartment.. they're plugged somewhere

mike

[Mike76251]

Originally posted by mike reeh


Been running "california gas" for years and never had a vapor lock problem even in the mountains.


mike

Forgot to mention...........I was towing 7000 lbs through Grapevine Pass when I had the problems.

[chevyfan420]

I have a big tank mounted at the front of the box. A line runs under the cab up to the inner fender where my vapourizer and regulater is mounted. The vapourizer is tied into a heater hose. It goes through both of those and into a strange looking carb that sits atop a factory GM spreadbore intake.

[mike reeh]

i find that fascinating.. let me know if you ever want to part with the complete setup.

mike

[1972C10]

Engines last alot longer on propane Old hank Hill would be proud ;

Looses power thou that motor should be nice and clean inside with little carbon if its been run on propane since it was new or rebuilt.

[chevyfan420]

ya, it dosent quite have the power it could but i can live with that. one nice thing about is that it needs no warm up time. it can be the coldest day and it fires right up and sits at an idle.

[crackajacka]

how bout mileage? how much does it get? i might look into it.