Re: 40hp Johnson 1963 Carb Question

[Don]

Jay-
That crazy low speed needle bushing on these carbs is a real pain in the rear end! Don’t know why the carb is manufactured this way, but it is. The white washers and packing should be enough to hold that silly threaded bushing from turning, but you never know. It is possible that the bushing is spinning inside the carb body while turning the needle, so moving/turning the needle is really doing nothing. Can you gently turn the needle in until it gently seats in the carb body? If not, the needle and bushing are just spinning inside the body, you may have to tighten up the packing nut some more. Once gently seated, back the needle out about 1.5 turns. Did you remove the core plug that covers the idle mixing pocket where the low speed needle works in the carb?
If not, it is possible that debris from the messed up needle packing got into the mixing pocket while you were cleaning out the old packing, this could cause idle problems by plugging the air/fuel ports in the carb body.
So, the engine will only start with the choke off, and runs poorly. Does the engine sneeze/cough, or just chug like it is overly rich, I guess it sounds rich from your description. The engine is lean is it sneezes/coughs. You would see fuel dribbling out of the front of the carb air inlet if the carb was flooding. Did you have the fuel pump apart? If so, perhaps it is leaking internally allowing fuel to spill into the crankcase through the pulse line. You could remove the pulse line from the fuel pump, then have an assistant pump up the fuel bulb, no fuel should spill out of the fuel pump pulse line nipple.
Your description of the throttle linkage sounds normal. The shift interlock linkage will prevent the throttle from being advanced too far when the engine is in neutral, which is what you described. And yes, once in gear, the throttle linkage will "snap back" from WOT when released to about half throttle, this is normal as well. Did you mess with any of these linkage adjustments? The carb’s butterfly must be "synchronized" to the ignition system or the engine won’t idle properly. Everything is probably OK if you didn’t attempt to alter any of the adjustments and got all the carb linkage pieces back together properly.