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Discussion Starter · #1 ·
I put my 1979 4x4 chevy 3/4 ton truck (350 Eng.) back in service to use on the farm. It had set for two years, i put a new battery in it and had to pour gas in the carb. about five times before it blew out black smoke and started running.Now the problem, once you start it, it will start and run all day,but after it sets all night you have to pour gas in the carb. to get it going. I put a new fuel fillter in the carb. and had the wife turn it over while i watched the flow from the fuel line,it had good pressure. Sometimes in the mourning it will start and run for a second or two then die and won't start till you pour gas in the carb. Anyone know if the fuel pump has a check valve to keep the gas from draining back, that's the only thing i can think of. :confused: Jack
 

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No check valve. The carb bowl should hold enough fuel to run 3 or 4 minutes if the fuel line was disconnected. Without it running, have wife pump the accelerator. Does the accelerator pump in the carb squirt gas into the manifold? If not, the seal on it has dried out and needs to be replaced.
 

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The rubber piston on the acelerator pump can be cracked or distorted, this ethonol gas is hell on rubber.

Just a guess ??

Also how's the vacum, is the choke closeing ??

Murrell
 

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just a wild one here going out on a limb but Im going to say it could be choke the choke is stuck open and when you pour gas in carb to prime. It is making it richer and thus allowing it to fire off once it warms up you dont need the choke so it starts and runs alright until it cools off enough to need the choke again
 

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Discussion Starter · #6 ·
Went out this mourning, it wouldn't start,i primed it and it would start and die. I done this about 5 times and quit (it's outside and it was snowing,26 deg. temp.) The choke works good :thumbsup: ,so i ordered a excelerator pump ($9.00) said it will be here in the mourning. I bought a 2010 4x4 truck last month and don't want to feed with it, the cows start fighting when i feed them grain and i've had them knock each other into the side of the old truck, a flat bed and i don't want that to happen to the new one. :roll: Jack
 

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I'm betting you put a fuel pump on it too. This ethanol gas with ruin the diaphragm in the pump also. If it's got a Q-Jet on it, the welch plugs in between the base plate and body were notorious for letting the fuel leak out of the bowl overnight also.
 

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Discussion Starter · #8 ·
Rast, i did buy a fuel pump for it yesterday when i ordered the excelerator pump, i was surprised it just cost ($21.00). It does have a 4 barrel Quad. on it,i haven't had one of them apart in years and hope i don't have to. I bought this truck new,gave $6,500.00 for it,i was sick when i drove it off the lot. I was wondering what have i done? how will i ever pay for it. :confused: Times have sure changed. :mrgreen: Jack
 

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You know you are going to have to pull the top off the carb to put the accelerator pump in. Don't forget those 2 little screws down in side the primary's you have to pull out and take the metering rods out also, less chance of damaging them. Only knock the roll pin on the accelerator arm through just far enough so the arm comes loose. Then use a screwdriver as a pry bar to push it back on reassembly.
My back is hurting already doing that on the motor.
 

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Discussion Starter · #10 ·
Rast, it's -1 deg. out today and the truck is out in the open,i've got the parts, but the weather will have to improve before i take this on. I'm going to try the fuel pump first,and i remember that little push rod that keeps falling down when you try to put the pump arm in the hole. if i remember right there is a bolt on the front you can screw in to hold the push rod in place?.As for the carb i'll just take it off and soak it in paint thinner overnight and go through it, if the fuel pumps not the problem.Something i'm not looking foreward to. :beg: Jack
 

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Jack, go to a garage and borrow a fuel pump pressure gage. Unhook the fuel line at the carb and check the pressure. Then take the fuel pump back and get your 21.00 back. Then fix the carb, or change the spark plugs.
 

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Ok, I'm old, forgot to mention, Fuel Filter, isn't that the ceramic filter inside the carb, were the gas line connects, Big nut.
Water will stop them up in a minute, then they freeze.

The gas pump has just a little pressure, your looking mostly for flow, just to keep the bowl full, Pull the line off, spin starter see if you get a flow. Place finger on line, pressure should spew a little gas.
{ Probably won't start, put pull coil wire anyway }


I'm betting on the ceramic filter, If I remember right, when they stop up you can even blow thru it but gas won't flow thru it !!

This was always a problem on my 396 !

Murrell
 

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Stopped fuel filter would not let it run after it is started. He says it goes all day, once running.

Fuel pump should have approx. 6 lbs. pressure. A quick check with a gage will tell you. I just replaced one on a Chevy truck that had 1 1/2 lbs. pressure. It would start, but only run 30 seconds or so. After it had time to fill the carb again, it would run another 30 seconds.
 

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Those fuel filters were made of sintered bronze and yes they would plug up bad with the use of bad gas.
I have rebuilt many of the old q-jets, Dad was an Oldsmobile man and ran those monster 455 motors in them. Have even cut out the air horn gasket from a manila folder.
 

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Discussion Starter · #15 ·
I put a new filter in it,the filter has metal on the ends but a corrugated cardboard looking material in the middle about 11/2 in. long, and yes you have to take the big nut off to get to it. I tried to start it yesterday mourning and it would only run on the gas i poured in the carb and then die. It may be froze, the temp last night was-1 and going to be the same tonight. Can't get back to it, i'm trying to keep the Mir Fount water tank from freezing. Jack
 

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Discussion Starter · #16 ·
Update.Well i put the new fuel pump on and a set of plugs, had to prime it to get it started. I hooked the 5 semi truck tire drag to the back bumper and drug the field where i wintered the cattle (took a little over an hour) it never missed a lick. I stopped 3 different times to pick up limbs and it restarted every time.(well that was yesterday)Well this mourning same thing it started and ran for about 30 seconds and died,i took the fuel line loose from the carb and had the wife turn it over, no fuel came through? took the other end loose and blew through it, it was clesr, had the wife turn it over and watched out put hole on fuel pump,nothing. I disconected the gas line between gas tank and the fuel pump, no gas ran out.I put it all back together primed the carb, it started and ran anytime i used it today. :confused:I'll see what it does in the mourning.Any idea whats going on. Jack
 

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Does it have a filter somewhere in the frame rail between the pump and the tank? Next guess is an air leak or rotten rubber hose, of course it'll be on top of the tank where you can't get to it. I'm taking it for granted that it's warm enough so there's no ice. We are seeing a lot of rubber fuel hoses coming apart on the inside and still look reasonably good on the outside.
 

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No Gas came out of fuel tank !

A short story, don't laugh;
A custemer brought in a big tractor, it would run and die,run and die. Checked tank almost full.
I've forgotten what kind of tractor, but it was gravity feed, took tank line off no gas flow, blew backwards gas run out, hooked it up started tractor it ran a few minutes and quit.
Repeated the procedure with the same results.

Ok, something in the tank, tried fishing in tank no luck, put rubber hose in and sucked vacum, and drained tank, could not see anything.
Removed tank, shook it, something ratteling inside, turned tank over shook it and something round and hard about 2 inch's long fell out, kept shaking and 3 or 4 more pieces came out.

Not wood, what the heck is it, looks like Dog ---- !
Put it all back together, ran fine.

Custemer , couldn't believe it.

Turns out he had made some neighbor kids mad and they had put dried Dog ---- into his gas tank.

It don't float but lays and moves around on the bottom and the suction/vacum of the fuel draining pulls it over the fitting hole, it's lite enough when the engine dies it will move away and let a little gas back into the line!

Murrell
 

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Discussion Starter · #19 ·
rast,that was what i was thinking,but didn't want to believe it,pulling the gas tank won't be a fun thing, (it's 3/4 full) i did put a new gas tank on it about 6 years ago (it's still got a shine to it). I'm thinking it's got a crack in a hose (on top of the tank) or a clamp that has came loose to let it suck air. The weather was in the upper sixties yesterday, and the only filter is the one in the Q jet, carb.The only other thing i can think of is the new fuel pump has a hole in the diafram(sp?), but that's not likely. :confused: Jack
 

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brooksbeefarm said:
The only other thing i can think of is the new fuel pump has a hole in the diafram(sp?), but that's not likely. :confused: Jack
I wouldn't think so either cause the symptoms are still the same.
 
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