Super cold blooded

[Sweeet67]

My 69 GMC K15 has a stock 350. It would start and idle just fine till a few weeks ago. I had the carb off a year or so ago and cleaned and rebuilt. It has an HEI distributor, new plugs and wires. I only run ethanol free fuel.
The choke seems to be working just fine. The butterflies close when cold and open when warm. Anyway, I will have to crank it two or three times while pushing on the gas 15-20 times before it will fire off. Oh, and a newer fuel pump. Any suggestions on where to start? Thanks

[geezer#99]

When you’re pumping the pedal how much fuel is the accelerator pump shooting in to the carb Venturi?
If it’s very little then your pump is suspect.
If it’s a lot you’re likely adding too much fuel, flooding it.

Should be able to step on the pedal once to set the choke and then once more to add a little fuel from the pump and it should fire up.

Two q’s.
1. While your cranking it over and pumping the pedal, is the choke blade completely closed.
2. What’s your initial timing?

[Chris_oz]

My guess is that the carb is dry of fuel and it takes the cranking to fill the bowl then it fires.
Before you crank cold next time, take off the air cleaner and have a look if you are getting any fuel when you pump the accelerator.

New fuel, even ethanol free evaporates and boils so much easier, if it's parked for a few days, carb will more than likely be dry.

[Sweeet67]

I will check the accelerator pump in the morning. I assumed it wasn’t that because I installed a pump less that a year ago.
I will also verify if the butterfly valve stays closed while pumping the pedal.
If I remember correctly, initial timing is 12-14 degrees.

[Sweeet67]

If it sits for a few days, there is no gas on initial pumping of the gas pedal. So it does appear to be evaporating or draining back to the tank. How do I prevent drain back? Is there a mech pump that has a check valve in it?
The choke valve is closing all the way also.
If timing is playing a part, should I retard or advance it?

[geezer#99]

Don’t assume it’s draining.
Pull the carb apart and check the accelerator pump.

[cleszkie]

I am assuming that you have a quadrajet carb since you didn't specify. These can develop leaks out of their fuel bowls past the factory installed brass plugs. If you have a big enough leak, your bowls will be dry within a day of sitting. This will require cranking the engine over several times to pump fuel into the carb before the accelerator pump in the carb has anything to work with. There are kits out there that you can buy to remedy this problem that consist of threaded plugs that replace the press in type plugs and marine epoxy.

[Sweeet67]

Yes it’s a quadrajet, sorry for leaving that detail out. I hadn’t thought about the the leaking bowl scenario. That’s a good point.
I did replace the accelerator pump about a year ago. And the reason I say it’s not pumping is just by looking down the carb and pumpin the linkage, I don’t see any fuel squirting out.
I’ll check again with it warmed up. See if it’s squirting then.
I’ll have to look into sealing those damn plugs on the bottom. I’m getting to be a pro at this along this thing off in record time anyway. Lol

[Sweeet67]

How much cranking should it normally take to fill the carb back up?
It’s been taking a good couple mins of cranking to get it up and running.

[geezer#99]

If you pull the fuel line off the carb and put the end in a quart jar and then crank it over it should fill the jar in 30 seconds.

[68 P.O.S.]

It should only take a couple seconds. After sitting a few days without running, my truck may take a couple cranks to get going, but it's less than 1 minute.

[demian5]

Well plugs leaking

[HO455]

It sounds like you may have more than one problem. Well plugs leaking down means the accelerator pump has to work in a dry hole. That usually eats the pump seal. Then you get no pump shot.
If it is taking several minutes to get fuel to the bowl you most likely have a weak fuel pump or plugged fuel filter.