the problems i have read about concerning vapor loack, is it mostly a problem in the line running from gas tank to pump or pump to carb (61' d100 p.u.)?

Generally pump to carb.

Some people have it and some people don't.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

fuel line mod fixes it.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Hey Fikey,
Dan's link is to the mod I posted about over at Norm's sweptline site-and-may I add-it works great! Also less cost than an electric fuel pump.
Good Luck
Todd

Keeping the fuel cool is always a good idea. I plan to re-route the line as described soon. Our car does not die outwrite but gets a rough idle and floods at shutdown in the heat we have down here, and thats with a fiberglass and silicone sleeve over the stock line. If vapor lock is more of a problem than normal for a particular car, try checking the fuel pressure. If it is low at idle the spring in the pump is tired. A couple of psi can make quite a difference. Or if your pump is really old maybe just replace it anyway. I have seen cars with vapor lock problems that could not seem to be fixed and it was just the pump. A weak pump can make the carb lean even at light loads. It is like setting the float lower. The fuel does not have to rise as high close the needle and seat since there is less pressure acting against it.

My vapor lock problem is the heat riser flap. I did the fuel line change, and it didn't change it. But with my heat riser, I can tell that it is the problem. When the motor is cold, the spring hasn't push it back. Once it warms up, the spring pushes it back. And I get the vapor lock about a minute or two after it warms up. So I was playing with that. And the spring goes back like it should. However, pushing it way back there, where it shouldn't be, is where I can hear the inside of there. And doing that, I can drive a lot further without problems. So I know it is messed up inside there. Since I am getting the super six on the 4th of November, I haven't worried about it. Once we take that old one out, we can see exactly what is going on. I am getting the whole super six from another car that is working great. So I am sure that will take care of my vapor lock problem. I would try the fuel line change first, but do a search on my ID notes ID, and you can see how all these guys helped me figure it out. I think you can search for my notes. If not, sorry.