Re: Gummed up carb never rebuilt a carb

Posted by DavidPackard On 2020/1/4 13:58:52

Johntrhodes81
I also vote with Jim/KB1MCV, 'jump right in to the deep end'. I started working on WCFBs, two at a time, some 50 years ago when I had a set on a '55 Chevy, and then fast forward to the single set-up on my '54 Cavalier. I would like to provide some suggestions based on my experiences.

Let's start by assuming there was nothing really 'wrong' with the carburetor when the car slipped into hibernation, and the task is to renew parts that do not hibernate well like rubber and leather parts. Plus there's the goal of cleaning the unit both inside and out.

I suggest/recommend:

1. Resist the urge to remove the throttle plates. Unless the throttle shaft has been abused or requires bushings there is more risk than reward in removing throttle plates.

2. As BigKev suggested disassemble the carburetor in a clean pan. I use a transmission oil pan, but only because I have one. A turkey pan from the grocery store will work just fine, or as suggested a cookie sheet, but later on when you're in the cleaning stage a pan with some depth will be an advantage.

3. Place the parts as you remove them into individual containers. I use tuna fish cans for the small screws and clips, and larger ones for the other 'stuff'. Watch those little hair clips they have been known to take flight during installation. Use a hemostat or needle nose pliers to hold-on to those clips.

4. Make sure you keep the primary and secondary parts in separate containers. The jets are different, so don't mingle them.

5. Do NOT invert the carburetor until the all of the springs and check balls are accounted for. There should be two check devices in the accelerator pump system. A ball and the bottom of the well, and a needle under the discharge nozzle. There a springs at the 'vacuumeter' and accelerator pump. The first time the carburetor body is inverted it should be done over a clean pan.

6. Lacquer thinner is a fairly good solvent for carburetor cleaning, and it's available at relatively low cost. I use a 'tinners brush' to wash the parts with solvent, and change the solvent when it gets real dirty.

7. Fuel 'shut-off' valves are currently available in two design configurations. The 'Daytona' kits will likely come with the 'flat disk' design valve. With this design the float level adjustment is via 'extra' sealing washers between the valve and carburetor housing (described in the instructions). The other valve design ( historically correct for a WCFB ) features a conic 'needle', as in needle and seat, and the float level adjustment is via bending the tang that closes the needle. The 'flat disk' design is not robust to side forces and therefore the tang on the floats should 'push' dead center on the valve. That's why the seats are shimmed with sealing washers. Again all of this is covered in the instructions if your kit has 'flat disk' valves.

8. I use a piece of cardboard holding a jet or air bleed in-place. I then hold the whole mess up to the sun or bright light bulb (cardboard shielding my eyes) and look up the bore of the jet/air bleed. You will be amazed on what you can see with only the small 'pin prick' of light shining through the orifice. If you can't see light, or the light is fussy, then the 'thing' must be cleaned.

9. Knowing from the specification sheets what the 'correct' diameter of the orifice is, I will use a number drill SMALLER than the specification diameter to clean-out the 'gunk'. Don't use a drill that is larger than the specified diameter. For about $10 you can buy a set of drills, numbers 61 to 80, on the internet. That size range will suit your needs.

10. Compressed air can be used to verify that large drilled passages are clear. You may not need to remove any of the aluminum plugs that seal the cross drilled passages. If the passages are sealed with threaded plugs feel free to remove them.

11. The carburetor kits that were available back in the '50 -'60s came with float level gauges . . . not so much today. I use a drill of the correct diameter to verify the float level adjustment.

12. Re-installing the metering rods can be a bit finicky in that the spring tends to push the rods out of alignment with the jet bores Take your time they do fit.

Other than 'take a lot of photos', that all I've got.

DP