Just taken my bus for its first run since August and it's not too happy with itself. It's a 1600 with 34pict4 carb, stock dizzy with leccy ignition in it. It started first turn of the key from cold which was nice, but has a flat spot when accelerating from idle (when pulling away from a stop it tries to die) and refuses to start when hot. it also pops when on overrun (throttle shut going downhill etc). The Carb has been cleaned out with all jets blown through since the last time it was run but I'm assuming i adjusted something accidentally when I put it back together. My gas tester is with a mate at the moment so I can't check mixture. The choke is working as it should and th[sub][/sub]e timing is correct. I can't find any air leaks anywhere either. Does it sound like its running too weak?
Popping on overrun would suggest a weak mixture. Has the throttle stop screw backed off slightly allowing the flap to close up tightly when you take your foot off the throttle.
Throttle stop is sealed with an end cap on so its not been adjusted at all. Think i know why it tries to die when the throttle is opened quickly. Accelerator pump isn't injecting any fuel when the throttle is snapped open. I looked down the carb throat and opened the throttle quickly by hand and no fuel was squirted in. Using a screwdriver i gave the accelerator pump lever a quick nudge and a nice jet of fuel was squirted in. Looks like the linkage doesn't move enough to move the diaphram.
I think the outlet from the accelerator pump is slightly blocked as its spraying all over instead of straight down the carb.
I'm gonna take the carb out and blow through the accelerator pump galleries with carb cleaner and see if that improves it. Not sure if a blocked accelerator pump would make any difference to hot starting but if I turn the fast idle cam round by hand so the choke is on it'll start fine.
It won't make any difference. If you're whipping the carb off, worth giving everything a good scrub with all jets out.
