Re: Carter WD-0

Posted by DavidPackard On 2022/2/9 13:24:08

Gary49eight

Remember the guidance from Carter, that is, confirm the tune-up items before the carburetor is condemned. That said, I would first look at the following items:

Fuel shut-off valve (aka needle and seat). Since you indicated iterating the float level I’m sure you are aware of the hardware. However, if the needle and seat are leaking I would also think the engine would stall at idle from ‘flooding’. Excessive fuel pressure is also thrown into this category.

Metering needles not installed correctly. If the needles are not blocking a portion of the main jet area, then the mixture would be ‘wildly rich’. Upon assemble the needles should ‘plunge’ up and down freely in the main jets. Smoothness of the ‘plunging’ also validates the vacuum piston is not binding.

If the vacuum piston is riding high from a poor piston fit in bore, incorrect return spring, or the fundamental adjustment of the ‘finger’ that inhibits the downward stroke as a function of the throttle position . . . any of those will push the mixture rich.

I believe one of those small round gaskets on the aft side of the carburetor housing is dedicated to the vacuum piston. If that is leaking the piston will ride high and push you rich. I believe you will hear a whistling if that gasket is leaking.

To complete the list, but I’ve never encountered this, the main jets may be loose, that is, not tightened in the threaded bore.

I would pull all of the spark plugs and confirm that all of the plugs show a rich condition. If 4 are rich, and the other 4 are OK, then that’s another list of items to check. I would do that before the next carb disassembly.

If you still have the brass tag, let us know the number.

dp