zenith issues

[troy]

hopefully someone can help me out ,i have a 62 88 with a zenith on it this is what is happening , it starts when things get warm outside , the thing will start ok but after it sits for a minute and you go to start it and drive away it runs out of gas , so i figured bad fuel pump or blocked line , changed the pick up tube in tank , changed fuel pump ( took both the fuel pumps i have apart and had a look inside everything o.k. ) changed fuel line , finally thought it might be a plugged filter because when i changed it it ran ok for a few days , then it did it again the other day , tried to prime the carb with the fuel pump on the side of the road and it felt like it wasnt picking fuel up so i thought well it must be the pump , i took the line off the carb and then tried the pump primer out and it worked fine,so i figured the needle and seat where stuck in the carb and the fuel pump was bypassing inside, i have another zenith that had a kit put in it before it was taken off the vehicle , so i pulled the needle and seat out of that carb and put it in the one iam running and sure enough when i took the needle and seat out of the one iam using it had a pretty good ridge on the needle so i thought it was getting stuck and not letting the fuel pump to fill the float bowl , so it worked well for a couple of days until it got a little warmer outside and i let the thing sit for awhile after running the vehicle yesterday and it did it again , this time i gave the float bowl a little wrap and you can hear the fuel start to enter the carb and then it ran fine , its also made this sound when ive taken off the inlet line to the carb you could hear the fuel rush into the carb as soon as the fuel line is taken off the carb . do you think the fuel could be boiling in the float bowl when the vehicle sits after running it ? if so does someone have a fix ? , this thing is my daily driver and ive never had this much of an issue with the fuel system before , and never once in the winter , so its heat related . i got the carb from charles kellog and ran it on my series 3 for years and then put it on my 62 and been using it for another 4 yrs , it was off a military unit from the u.k. , ive had it apart a couple of times to file everything flat in the past , and its worked really good until now , i have a elec pump but i would like to leave the mech pump on ,i dont think changing the pump would cure the problem anyway, plus the 88 is positive ground . any help would be most appreciated. troy

[gudjeon]

I went had three mechanical pump in a row that pooped out on me in the past. I went to an electric pump from NAPA so I did not have to rely on a distant part source for a "disposable" item. I also hooked up a bypass filter used on 80's spec Chrysler stuff. Modern fuel formulations are meant to be pressurized fro fuel injection and are not stable in an open carb system, and it gets worse with heat and altitude. Recirculating the gasoline keeps it pumping under a higher pressure and it stays cooler. An added bonus is that it is constantly filtered and this filter is still made of metal.

Also, check that your "dead spot" is not caused by the accel pump sticking. I had mine do this and you need to check that the small ally pump itself is free, not the plastic plunger inside of it. Some PO's set it very rich to compensate. Also, I found these carbs to flood silly if the float level is even the slightest over spec. Set float, turn upside down and you can blow into the fuel inlet to see if the needle and seat is working, a bit like the float valve in your normal toilet.

Here is pics of what I did. recirc system with an electric fuel pump. I even went and mounted the pump on the bulkhead and it works like a darn. No more vapour lock, easy hot starting, and no more boiling fuel at altitude - which is all we have around here.

http://i35.photobucket.com/albums/d187/ ... ump1-1.jpg

Ran the 1/4" line back to the tank. The filter has a small orifice in the relief line to return fuel and lessen the line pressure. Also, no pressure is left when it shuts off.

Good Luck

[troy]

thanks , i set the float again after posting and checked everything else out , did replace the economy valve ( i believed thats what its called ) the little diaphagm on the carb above the float , accelerator pump looked good , i have an electric pump here but the truck is positve ground , i guess i could isolate the pump . troy