I'm working on figuring out a vapor lock problem on the Lark I got from Kelly. Theres a canister and a return line from it to the tank. nothing on the pump its self. the line coming from the engine to the canister is plugged off and I don't see anyplace on the carb for it to go. Ideas????
Hey steve, if I am not mistaken, the qjet on there is a 74+ smogger, and I think you will be one nipple short. I was going to get a vacuum line tee and split it off. The motor was from an a/c car, but I changed the fuel pump to the non-a/c skylark... KFD
That isn't a return line, it's the vapor canister line. The vapor canister has two lines going into it. One comes from the tank, the other either goes to the carburetor, or simply fits into a hole in the bottom of the snorkel, or it fits onto a nipple on the air cleaner housing. It is an evaporative emissions device. A fuel return line runs from the fuel pump back to the tank via a steel line. Not all engines had one. The A/C equipped cars got it, and most if not all big blocks.
On the newer qjet, there isn't a provision for that canister line, and it has a non-a/c fuel pump on it. Spoke to briz this morning, and he said vacuum advance was bad. No big. I am having my dad look around the garage for the one that didn't make it on the car... KFD
The evap line can also be tee'd into the egr vacuum line in some cases. That's how mine is run for '73. Evap shouldn't cause vapor lock though (for those reading this later).
That should have no effect on vapor lock hooked up or not. several times he's had fuel boil over and a lock. Not really worried about it to much as the 455 Im getting (from "Toymobile" if memorie serves correct) will be going in next week.
I'd just swap on an A/C style pump and run the return to the tank. If that's not enough than add a spacer under the carb to reduce fuel heat even more.
I think if I did that I would have to use the vapor line as a return to the tank. I have a pump from my 430 riv parts car that has the return on it. maybe the pumps are the same except for the return line.
