1977 Carb HELP (1 Viewer)

[bwell]

I followed pin heads carb tutorial and went through it.

I got it started yesterday on its own with a new battery, new negative wire attached to cleaned up ground connection on the frame. Initially the gas bowel was over filling and running out the primary when engine was turned off but that stopped once I got the idle adjusted and ran it for awhile. Choke settings are working great.

I need some suggestions on where to start. Once warmed, it falls on its face with any kind of throttle input other than very slight throttle input it will eventually rev up.

Do I need to focus on finding vacuum leaks first? I was planning on following the guidance in a few older threads using the cardboard of the carburetor inlet to start.

I'm sure something is off with the ignition somewhere it doesn't idle like it should. I know when I tested the secondary diaphragm assembly depressed all the way against the back it would pop out to its intended shape but hold until I released the inlet.

I put the jets back in the exact way they came out. It always ran great how it was assembled after he rebuilt the carb years ago.

Jet primary- 36
Jet sec - 171
Jet primary slow 75
Jet sec slow 10
To me the slow jets seem like they're reversed.

Any help or direction would be helpful. Not trying to throw a fortune just getting it running right.

 

[Pin_Head]

It could be a vacuum leak, so check.

The numbers on the primary main jet and secondary slow jet are probably missing a digit somewhere.

 

[FJ40Jim]

Falling on its face w/ throttle input is likely a problem with the AP circuit.
The stock jets are mains 136/171, slows 75/110. drill the 136 to 1.45 and the 75 to .85 for better driveability. Stock primary jets are both too lean.

HTH

 

[bwell]

Thank you both for the insight. I probably did jumble something up in assembling it. Replaced all small vacuum hoses today, almost 20' of it. Tried the wd40 around the base of the carburetor and some other areas.

Pump inlet ball and tiny retainer spring- pretty sure even when I disassembled it the retainer spring wasn't actually "retaining" the small check valve ball. - is this a absolute or won't run correctly?

Also- solenoid valve is working correctly- vehicle dies if unplugged.

The few plug wires I pulled today seemed to be working quite well.

Hopefully I will get it taken back apart tomorrow and see if I can figure out what is going on and quadruple check all of my measurements on assembly.

 

[Pin_Head]

If the inlet check valve is not seated in its hole, the accelerator pump won't squirt. It is pretty easy to check by looking inside and opening the throttle manually.