gas

[48gmc]

have a 48 gmc with a rochester 1 barrel...started yesterday ran for awhile the guit, would not start back up...looking at my glass filter on the gas line, had little gas in it, would keep cranking but will not fill up glass, took top of carb off, the gas was probably 3/8 from top of carb. i let it sit over night today it did the same thing. i have a beer keg in back, rubber line running to pump, my new one, then to carb, floats adjusted according to specs. i am learning and getting frustrated, any info would be great.

[mongocanfly]

Is your tank vented properly?

[48gmc]

how should it be vented?

[48gmc]

i think the gas cap is the vent.

[joedoh]

to check the vent just take the cap off and crank it. if the filter fills up you have a vent problem.

if it doesnt, check your metal line for kinks and your rubber line for collapsed sections. check your fuel pumps for operation. I havent ever used a beer keg but you probably have a combination of new line and old line being used.

shake the tank in case some crap is blocking the line where it enters.

[mr48chev]

Go with What Joedoh said in post 5. That is simple and doesn't cost a thing until you fix the problem.

Tank not venting will cause it to stall when the pump creates a vacuum in the tank that won't let the pump pull any more fuel as there is no air to replace it. The lower the fuel level the longer it takes to stall. That's from the guy who drove 4 miles with a non vented cap on a rig requiring a vented cap with 1/4 tank of gas and then walked to a gas station and carried a gallon of gas back and put it in while it actually still had gas in it.

Kinked fuel lines be they rubber or steel. Check it from one end to the other.

Plugged fuel filter if you have one close to the tank and you should have one back there. Unknown tanks often have crud in them just dirt or metal residue that will plug an inline filter rather quickly the first time you run the rig. The sediment bowl is cute but it only catches the biggest chunks of grit.

If things still don't work check the orifices in the fittings in the fuel system. I had one rig that someone had put a natural gas fitting in the line between the fuel pump and the 2 four barrels and it would take off hard and then stall out and when the carbs filled again it would go again until the bowls ran out again. Fixed that and it ran hard though the gears.

[dsraven]

I have had trouble with the valves in the pump sticking

[48gmc]

i took the cap off, still the same. everything is new. the tank i cleaned out good, had fit installed in bottom of tank, left 1 1/2" sticking inside of tank, so it wouldn't draw from bottom, know kinks in rubber line, installed new fuel pump, did the same thing, from fuel pump to carb is rubber line, know kings. i took carb apart, check to see if any holes in float, ok...cleaned all out, put together, still same.still alot of gas in carb, seams like it should run...will chack for spark. i replaced everything, plugs wires coil distributor cap.last year i ran the truck, going on short run , truck ok it is when i went to lake george which is about 30 mimutes from my house, went up fine, coming back it started acting up.got about 3 miles from house wouldn't start no more.

[mongocanfly]

Sounds like you've got gas..check for fire..

[dsraven]

if you have spark pull a plug and check for spark first, then advance mechanism in distributor for sticking. does it fire at all? valves adjusted ok? maybe time for a complete tune up including compression test, distributor check, etc?

[48gmc]

haven't had time to check, working on moms car, will check soon.

[48gmc]

not sure what is a weak spark and what i a strong spark... getting blue spark on plugs, seams like some sparks where bigger than others.took off middle wire off distributor cab, hook plug to it, seam better spark from coil than distr. everything on put on is new, i might have put on 50 miles altogether, should not have to have these problems.

[mr48chev]

If that pickup tube is as high off the floor of the tank as I read you say it is you will need at least five gallons of gas in the tank to be able to pick the fuel up reliably. One of my rigs needs about two gallons of gas in the tank to run if it runs out. That cost me and extra walk to the gas station one day.

[48gmc]

i will have to check.