Truck turns over but won't start

[SilveradoDude]

85 C10 305 4 bbl Quadrajet

Ok, admittedly I haven't started the truck since February (After a recent carb rebuild). The truck started just fine back in February.

So I go out yesterday and nothing. I spray some starter fluid in the carb and she starts right up ....for 3 seconds. Once the starter fluid is used up she dies.

I disconnected the fuel line, put the line in a small cap, tried to start and it looked like the pump was delivering plenty of fuel. So I know I am getting fuel and I know I am getting spark because the truck does start up with the starter fluid.

What should I look at next? Carb adjustment, timing?

[mongocanfly]

did it ever run after the carb build?

[SilveradoDude]

Originally Posted by mongocanfly

did it ever run after the carb build?

Yes sir. I spent 2 days tuning it.

[mongocanfly]

with the breather off can you manually work the throttle and see if it sprays gas into the venturies
when I still had the smallblock ,the filter in the carb where the fuel line is got plugged up once

[Dead Parrot]

If it starts and runs with either start fluid or a small amount of gas poured in the carb, timing/ignition should be good.

Things to try in order:

Spray some carb cleaner down the vent and wait a few minutes before trying to start. Possible the gas turned to goo when it evaporated.

Unscrew the idle mix screws a couple of turns and try starting. If it starts, readjust after a few minutes.

Possible the needle/seat/float stuck shut while it was sitting. Try gently whacking the carb with a rubber mallet on one of the solid parts.

[rpmerf]

Agree with above. Just because the fuel pump is pumping fuel, doesn't mean it's getting to the carb. It's not unheard of for the float needle to get stuck.

You will know the bowls are full when you crack the throttle, and see the accelerator pump squirting fuel.

[SilveradoDude]

So I pulled the carb and then I pulled the filter, the filter and the insides of the filter housing was covered in this white powdery crap. Pretty sure that's what is causing the issue. I will clean everything put in a new filter and try again. Any ideas on what this stuff is?

[mongocanfly]

Mine was gummed up with a overabundant use of thread sealant on fuel line fittings from the PO...
Sounds like you may have corrosion somewhere in your system...you might want to add a inline filter between pump and carb..

[Dead Parrot]

My guess would be water. Lots of ways some can get in gas. Normally not a problem but the insides of carbs expect gas and react poorly to water. As the gas evaporates, the water is what is left.

When you get it running again, might be a good idea to run that tank dry and refill with fresh gas or the problem may repeat.

[rgunlock]

Might just be residue from today's crap gas evaporating while the truck sat a few months. This one sat a lot longer than yours, but you see what I mean.

[demian5]

I had a sticking check valve in the fuel filter on the carb causing issues for me.

[SilveradoDude]

Cleaned everything, Replaced fuel filter, new intake to carb gasket. Truck did not start. Checked the fuel line, line and filter are BONE DRY, no fuel.

[mongocanfly]

sounds like you need a fuel pump

[SilveradoDude]

Originally Posted by mongocanfly

sounds like you need a fuel pump

Looks that way.

[SilveradoDude]

Replaced the fuel pump, still can't get any gas to the carb.

[SilveradoDude]

Question, if I wanted to test an issue with either the line or the tank I could just drop the inlet port line ( the fat one) into a gas canister (perhaps raised above the engine for gravity flow) and test it that way correct?

[kipps]

Disconnect the fuel line as it enters the fuel pump. Push a foot or two of hose onto the pump, and drop it into the open neck of a fuel can. The fuel canister can be sitting on the ground, and it should pull from it fine.

I started a c60 dump truck this method. Started and ran perfectly. Once I had it running, I replaced the fuel line back to the tank, and was able to drive it.

[SilveradoDude]

Originally Posted by kipps

Disconnect the fuel line as it enters the fuel pump. Push a foot or two of hose onto the pump, and drop it into the open neck of a fuel can. The fuel canister can be sitting on the ground, and it should pull from it fine.

I started a c60 dump truck this method. Started and ran perfectly. Once I had it running, I replaced the fuel line back to the tank, and was able to drive it.

Thanks, and the inlet line is the larger of the two hoses correct?

[kipps]

Originally Posted by SilveradoDude

Thanks, and the inlet line is the larger of the two hoses correct?

I was talking about just pulling a line down from the fuel pump, and bypassing the chassis fuel line altogether.

There's no reason you can't pull a hose off the tank sender unit and do the same thing. I assume your '85 will have two hose connections on each tank. One, usually larger, goes to the fuel pump and the carburetor. The second goes to the charcoal canister or a filtered vent somewhere. Trace the fuel lines if you're unsure which is which.

[SilveradoDude]

Originally Posted by kipps

I was talking about just pulling a line down from the fuel pump, and bypassing the chassis fuel line altogether.

There's no reason you can't pull a hose off the tank sender unit and do the same thing. I assume your '85 will have two hose connections on each tank. One, usually larger, goes to the fuel pump and the carburetor. The second goes to the charcoal canister or a filtered vent somewhere. Trace the fuel lines if you're unsure which is which.

Right, the larger hose is the fuel inlet and the smaller hose is the bypass line that goes back to the tank...correct?

[Dead Parrot]

Another thing to check is the suction line from the tank to the frame line. About a year ago, a mouse chewed holes in both of my suction lines, (dual tanks). Had the rather irritating situation of having fuel starvation at the carb with two full 20 gallon tanks.

Your planned test should narrow things down.

Pretty sure that the 3/8" is the suction and the smaller is the return. My 75 doesn't have the return.

[kipps]

Ok. I'll admit that I'm not acquainted with fuel returns on carbureted applications. My only experience with a fuel return is with mechanical diesels, and with in-tank-pump tbi setups. My advice above was assuming that you had a common mechanical fuel pump and carburetor with no return line.

Guessing here, but I believe you could still feed the larger inlet hose from a fuel can, and allow the return to dump back into the tank by the factory method.