Kids and carbs. Education needed.

[Noahr63]

The young ones like myself have little to no experiance with carbs. I have peraonally only delt with small engine carburaters myself not always succesfully.

I have a 63 gmc 1500 with a 305 and the 4 speed. Im assuming its the stromberg 2bbl carb. On two seperate occations the truck has left me frusterated and on the side of the road. She seemed to run good...although without any choke there has always been a strong hesitation upon takeoff since i have owned her. She seems to die out and then revs.Previous owner claimed to have rebuilt the carb. Both times she would sputter as if choking out and then die. Nothing seemed to work for a restart. I poured gas in the carb and she would run off of it and then die before i could add more. On a side note gas seemed to leak out of the side where the throttle cable connects when i added gas .to much?after about 45 minuted i was able to get enough gas in and she ran under ger own fuel. Is this a carb issue or maybe the fuel pump. Im no mechanic but i am eager to learn . As she means so much to me id like to be able to claim that i have done all repairs myself if possible.

On a side note she is currently running an oil bath breather on the carb. Im sure this is stock. Id like to run a paper element however i do not know where to get one that would fit. I took part or the cleaner in to see if anything from a parts store would fit however almost everything was way to big to fit the carb. Any ideas?

[WE7X]

The first thing I would attempt to determine, is if the problem is fuel or ignition.
Form what you describe, I think it could possibly be either.
Ignition coils, and ballast resistors can intermittently fail from heat, and Vapor Lock is usually attributed to heat also.
If no ignition, then adding fuel will not help, but will flood the motor, and sitting is the only cure. Sitting also cools things down so any potential Vapor Lock may go away also.
I also have a '56 GMC with the factory 330+ Cu. In. GMC V8. It suffers badly from Vapor Lock, after idling for 10 minutes or so. It slowly dies as though it rans out of fuel ( which is what Vapor Lock causes).

Once you know it is fuel and not ignition, then meaningful work can be done to solve the issue.

Keep us informed.
Rod J
Issaquah, WA.

401's and 478's

[Noahr63]

I was leaning twords fuel because adding fuel to the carbs seemed to get her going. But only long enough to die again. As if sge just ran on what i dumped in the carb.

[bobdylan]

pull the fuel line off that goes to the carb, turn the engine over, capture the fuel into a jar, you will be able to see if pump is working. also pump the throttle, with enginge not running, looking in the carb, should be squirting fuel into carb, if not bad accelerator pump. If all that is working check your float level. Check point gap, check to see if points are pitted.

[bigblockv6]

On a side note she is currently running an oil bath breather on the carb. Im sure this is stock. Id like to run a paper element however i do not know where to get one that would fit. I took part or the cleaner in to see if anything from a parts store would fit however almost everything was way to big to fit the carb. Any ideas?[/QUOTE]

For a paper type air cleaner if you intend to keep running the stock carburetor, a GM 2bbl air cleaner assembly from the mid 60's to 70's that used the Rochester 2G or 2GC carburetor, preferably from a V8 truck.:ok:

[jrmunn]

Start with simple things. Change the fuel filter and install new points. I had a similar stop and start problem that I was sure was lack of fuel but turned out to be bad points.

JRMunn

[Noahr63]

Are points reletivley eazy to do for an aspiring back yard mechanic?

[Jeannie]

Noah,

Lack of gas or starvation could also be your filters. You should have one inline by the carburetor and also a canister style under the passenger side of the truck under the cab.

Good luck,

-Jeannie

6066 GMC Club

[GMC Guy]

You are welcome to check out the pics of my oil bath air filter modification to a paper filter. Let me know if you have a problem with the link? https://gmcguy.shutterfly.com/pictures/1449

[ilvracn]

do these trucks have a screen in fuel tank? if there is alot of debris / rust in tank, it can plug screen. after sitting awhile the sediment falls away from screen allowing fuel to pass until screen plugs again. when the truck wont start, pull the outlet line off fuel pump and crank engine. if fuel pumps out while cranking the pump and tank are ok. if no fuel, remove inlet line from pump have some crank engine, hold your finger over inlet port on pump. you should be able to feel suction. if no suction, replace pump

[jrmunn]

Changing points is not hard, but GMC did their best to make it that way. From what I read, the 60-66 V6's can have two types of distributers, one with a large rotor under the cap, and the other with a small rotor. Both are at the back of the engine where they are awkward to work on. Mine has the small rotor model that has the points screwed into the base under the rotor where they are simple to remove and install, but the gap adjustment requires turning a screwdriver placed in a slot while separately loosening and tightening the hold-down screw while the points are positioned where the cam lobe gives the widest separation. My experience has been that this is basically a trial and error method that one keeps doing until the gap is correct. The gap measurement is made with a metal feeler gauge.

Once the gap is set, a dwell meter can be used to see if the points are opening and closing within the specified degrees of rotation. I don't know if this is essential, but it helps me know that things are working right.

Timing should be checked after changing points, and adjusting timing requires loosening the distributor hold-down bolt , which is in a hard-to-reach (for me) location under the distributor. I use a crows-foot on a ratchet extension to do this. Once loose, the timing can be advanced by turning the distributor toward the vacuum advance housing and retarded by turning the other way.

And while you are at it, this is also a good time to install a new condenser.

Good luck with this. Original equipment points do wear out and need to be changed. More often in my case because the resistance wire that is supposed to limit ignition voltage after the engine starts is not working, which causes the point contacts to burn out more quickly. This can all be fixed by installing a Pertronix ignition system that I hope to get around to someday.

JRMunn

[TJ's GMC]

A friend of mine who has owned Lot's of these v6's over the years told me that if the fuel pump itself is bad, the engine will normally still Idle, but will not accelerate.

[Noahr63]

I was talking with someone a lot more knowledgeable than my self and this is what I have done. As simple as this was and a drive around the block I have a temporary fix. if I get stranded because im overly confident I will let you guys know hahaha! when looking at the carb I was told to play with the throttle to see if there was any play or slack before the accelerator pump engaged. there was some. I was able to bend the rod between the accelerator pump and the butterfly on the throttle to get rid of that slack. As it seems for now everything is a little more responsive and the hesitation upon acceleration is all but gone. It is worth noting that before I did this the truck was hard to shut down once warmed up. it wanted to keep running. now it seems to shut down just fine. I also let it sit for a day and I did not have to pump it to get it started. before I did this I would have to pump it at least 10 times to get her started.If anything changes I will let you guys know.thanks for all the helpful knowledge and imput

[TJ's GMC]

Good to know it's running good!

[Clarke]

You are welcome to check out the pics of my oil bath air filter modification to a paper filter. Let me know if you have a problem with the link? https://gmcguy.shutterfly.com/pictures/1449

I did the same air filter mod to my oil bath housing several years ago. Although, looks like oil bath is a different size/style. I don't know why hey are different, but I thought I'd share due to the difference. I included the paper filter part number in one of the photos...

[Noahr63]

https://m.youtube.com/watch?v=816LfX6iuRA
A video of her starting today!

[TJ's GMC]

https://m.youtube.com/watch?v=816LfX6iuRA
A video of her starting today!

Nice video! Sounds good. Subscribed to your channel.