6 cyl. gmc vapor lock??

drove this ole girl in a vet's day parade in tallah***ee today and it vapor locked on me any ideas on how to stop it?? by the way happy vet's day guys........

 

i must not be hamb friendly.... it's an old amphib truck called a duk...

 

old trick that always worked on my old DeSoto....wooden clothes pin on the steel line that went by the exhaust manifold...Don't ask why...it just worked...!?!?

 

Check fuel pressure,see if it is within specs,pressure helps with vapor lock

 

The GMC trucks we had when I was in the Army were Korean war vets. They had electric fuel pumps and so couldn't vapor lock.

 

thanks guys, ill try the clothes pins and i think the electric fuel pump could help. its a mech. pump now....

 

What the @%$!! is that?
Yeah, the cloths pin thing is an old trick! I'm thinking it actually works - but don't know. I run a couple on our roadster flathead mill. No hood and I have two there - between carb and fuel pump. The best part is to have the uninitiated ask "What the hell is that?". A real conversation starter. They usually chuckle in wonderment...

 

That always when you take a Duk out of water..........

 

yea its an old remedy my Dad used them on our 39 pontiac coming to ca. in 44'. He used to have a orange or a g****fruit in the cooler and in emergency would squish half of it over the fuel pump to cool it. Also had a DESERT bag hangin on the bumper. I think the clothespins acted like heat sinks.

 

that should be a military 302... 100% sealed ... and should have a seal dizzy, electric fuel pump and so on.

 

thanks for the help, looks like the clothes pins win, i dont know the duk very well , just ask to drive it , but what i could see its a mech. pump... but i agree it needs an electric pump...

 

If it's a WW2 Duk it would have a 270. If it has a Military 302 in it there is no boss or hole for a mechanical fuel pump. Been a long time since it left the factory. Who knows what has been replaced?

 

Thermal heat sleeving around the fuel lines, sold in most speed shops and mail order catalogs, sorry since the clothes dryer era, I don't have any clothes pins to send you. BDM

 

My 53 chevy ran perfect until the extreme heat of this past summer.I just clipped on some clothes pins and the problem was solved.

 

We were far ahead of the game back then we used 'solar drying].

 

If it's not too late for .02. My old man used the clothes pins or made small 'flags' from aluminum foil & w****d them around the fuel line. Seemed to disipate the heat real well.
BTW my dad drove a duk in WWII.
AL

 

thanks al and thanks to your dad for his service....

 

If not really late for my .02. Three things that come to my mind: 1) Does the vehicle stall, then will start right up? If so I would check the fuel cap for proper venting. 2) The poor excuse they call gas may be causing it too. The Octane rating (imo) don't mean jack! Try using a higher octane gas and see if this fixes it. That at least will tell you what is going on. 3) If you have a bowl filter at the carb, open it up and check the gasket to see if it is closing up. I have a 54 Chrysler with one, and the gasket was sealing up at the 4 slots that need to be open. You can buy these gaskets on EBAY for a buck a piece or so. Good luck.

 

Vapor lock is a ***LATIVE thing. Start by tracing the path of the gasoline all the way from the tank to the carb. Any point where the gasoline can gain temperature is a possible cause of vapor lock. When gasoline reaches the boiling point anywhere along it's path, it produces 'steam' which forces the gas away from that point in both directions...back towards the tank, and forward toward the needle valve in the carb...leaving you with a flooded engine and no gas in the line.
An electric pump in the rear helps by applying a slight pressure to the line which raises the boiling point. A forward mounted pump ****s a slight vacuum in the line lowering the boiling point. A fuel line clamped to a frame rail that is near the muffler will absorb heat from the frame rail,...etc. etc...

JG