73 Chevy C10 won't start / no fuel ? Help?

[deathcharge]

I'm new here. My Dad passed away and I got his old 73 chevy truck. I have zero knowledge of carburetor engines. For as long as I can remember it has always had trouble starting. We always had to climb up in the motor and pour some gas down the top of the carb to get it to start. I know my dad had the carb rebuilt and that didn't fix it. He took it to another mechanic that just replaced stuff. Fuel Pump , fuel filter, fuel lines I believe; and that didn't fix the problem. The truck will start right up if it only sits for a few days; leave it set for longer than a week, forget it, it won't start.

I think the last mechanic said fuel pressure was good, he adjusted the choke?. He said you may have to pump the gas pedal 6 or 7 times but it always started for him but he never let it sit very long either and then tried to start it.

is this a common problem with letting a carb engine set for weeks?
Any ideas anyone?

Thank you ahead of time.

[mongocanfly]

welcome
if I'm reading this right, the truck does start and run if its only sat for a day or 3
and what your saying is then it takes pumping the pedal 5-6 times to crank...
all the older trucks with carbs I've driven required the 5-6 pump method and choking to crank...after sitting for awhile the gas evaporates. ....or leak out of the carb..

[RotaryRocketeer]

Sounds pretty normal to me. The fuel evaporates from the bowls and the mechanical fuel pump is driven off of the cam, so the engine needs to crank in order to bring more fuel up to the carb. Once it gets fuel and fires, the engine is spinning the cam quickly enough to really get the pump flowing fuel. An inline fuel pressure gauge is an easy add on and could help diagnosing any other problems.

[deathcharge]

Well I can pump the pedal 10 , 15, 20 times and it won't start. Nothing works other that pouring gas in to the top of the carb.

So the engine has to be actively cranking for the fuel pump to work? I assumed if the key was on the fuel pump had 12v and was running.

[Racmad2019]

Sorry to hear about your Dad. My 73 GMC is the same way...that's another reason I use to drive it all of the time so I won't have that problem. Can you post a pic of your truck?

[Bandit130]

[deathcharge]

I just read about removing the mechanical fuel pump, installing block off plate and add a electric fuel pump. Does that sound like a good idea?

[mongocanfly]

"So the engine has to be actively cranking for the fuel pump to work?
I assumed if the key was on the fuel pump had 12v and was running."

1.yes ...the engine has to be cranking over for the mech pump to work...
2.not true.. the mech pump has nothing to do with the key and 12v...unless its been changed to electric pump...
unless the pump is bad there's nothing wrong with a mech pump....but it will be fine with a elec pump....sounds more like you have a carb issue than a pump issue...

[Dead Parrot]

Q-jets are noted for having leaking fuel bowls.
As others have noted, given enough time, the fuel will simply evaporate from the bowl.

If the bowl is empty, pumping the pedal does no good as there is zero gas for the accelerator pump to squirt.

Check the rubber suction lines from the tank(s) to the fuel pump. If they are original, they are well past end of life and could be allowing air into the gas lines, making it harder for the pump to suck gas.

On my 75, I will give it one or two pedal pumps and try starting. Depending on how long it has sat, it will either start right up or require several seconds of cranking to get fuel back into the carb.

I suggest you keep the mechanical pump. It is a simple normally reliable setup.

[cadillac_al]

When any of my trucks sit for a week I don't waste time pumping the gas when the carb is empty. I crank it 8-10 seconds until the oil pressure comes up and then I give it a few pumps. It fires right up then. I could pump it 100 times before the gas gets there and nothing will happen. Once you understand how everything works it's pretty simple.