85 Burban 350 Wont Start

[keefus1971]

I have an 85 Burban 4x4. All stock 350, Quadrajet, Stock Cap and Rotor. A few weeks ago I replaced the oil pan gasket. Took it for a test drive and it died on the highway like it ran out of gas. Towed it home replaced the fuel filter and it ran fine for a few days. Then the same thing happened again. Drove around town and it died like it ran out of gas. Pulled the fuel pump off and the spring was broken on the pump arm. Replaced the pump and its been driving fine. Got into it this morning it started up then died. Now it won't start. I've had the truck for about a month now, was told it used to be a farm truck so it might have sat for long periods. The idle on it hasn't been right since I got it. Some days it will be just fine. Others, when I come to a stop I have to hold the brake down and keep one foot on the accelerator to keep it from bogging out. Was told that the carb was rebuilt recently and it seems to look pretty clean. I did notice that the mixture screws on it are wrong and have some kind of square head on them. Not a flat head screwdriver type. I love the truck but gezzz this fuel problem is driving me nuts. Any ideas what it could be? PLEASE HELP!!!!

 

[keefus1971]

figured it out. Little plastic "valve" at the end of the fuel filter was stuck. Pushed it thru with a capri sun straw and runs like a champ now. Still has idle issue from time to time though.

 

[diesel4me]

That "roll over valve" caused a lot of grief on older carbed trucks...I used to use the older fuel filters that had none,or pulled that thing out and tossed it away--or better yet,just get rid of that stupid paper element and put a real "inline" gas filter on it instead--so I'd never have to worry about stripping those fine threads in the carb ..

Those mixture screws were probably correct,they are "tamper proof" and originally had plastic limiter caps on them that prevented them from being moved more than a full turn either way--they sell special "double D" tools that fit them ,if you can still find one--I used to use a hunk of 1/4" brake line with one end slightly flattened as a tool to turn them...

You probably have water in your gas tank,or rust...I'd definately put a lager inline filter in the fuel line so you wont be clogging that hard to change paper one multiple times--might not hurt to stick a magnet on the bottom of the tank to keep any silty rust from getting sucked into the fuel line or clog up the "sock" in the gas tank..

.also I'd check the steel line going from the tank to the carb end to end carefully for any rusty areas,a pinhole on the top side of one can let air get sucked in but not really drip any fuel out,and that'll reduce the amount getting to the carb and let air bubbles mix in with the fuel--one truck I had ,I found just that situation,after replacing the gas line it felt like it had 50+ more HP!..

.I also had one truck that had a factory rubber hose joining two sections of steel fuel line right near the rear wheel,that was all mushy and collapsed inside,replacing it solved a perplexing stalling out under heavy loads or hill climb problem the truck had for months!..(and was why it was sold to me at a real cheap price,after the pevious owner had put a lot of new parts like carbs,fuel pump and complete tune ups that did nothing for it!)...

 

[keefus1971]

That "roll over valve" caused a lot of grief on older carbed trucks...I used to use the older fuel filters that had none,or pulled that thing out and tossed it away--or better yet,just get rid of that stupid paper element and put a real "inline" gas filter on it instead--so I'd never have to worry about stripping those fine threads in the carb ..

Those mixture screws were probably correct,they are "tamper proof" and originally had plastic limiter caps on them that prevented them from being moved more than a full turn either way--they sell special "double D" tools that fit them ,if you can still find one--I used to use a hunk of 1/4" brake line with one end slightly flattened as a tool to turn them...

You probably have water in your gas tank,or rust...I'd definately put a lager inline filter in the fuel line so you wont be clogging that hard to change paper one multiple times--might not hurt to stick a magnet on the bottom of the tank to keep any silty rust from getting sucked into the fuel line or clog up the "sock" in the gas tank..

.also I'd check the steel line going from the tank to the carb end to end carefully for any rusty areas,a pinhole on the top side of one can let air get sucked in but not really drip any fuel out,and that'll reduce the amount getting to the carb and let air bubbles mix in with the fuel--one truck I had ,I found just that situation,after replacing the gas line it felt like it had 50+ more HP!..

.I also had one truck that had a factory rubber hose joining two sections of steel fuel line right near the rear wheel,that was all mushy and collapsed inside,replacing it solved a perplexing stalling out under heavy loads or hill climb problem the truck had for months!..(and was why it was sold to me at a real cheap price,after the pevious owner had put a lot of new parts like carbs,fuel pump and complete tune ups that did nothing for it!)...

Thanks for the input. I've got a good weekend project now.