77 Spider cold engine issues

[jc_wisconsin]

I have a 1977 Spider with a carb that takes a while of cranking to start. Then is sputters and bogs down when accelerating (unless I get the RPMs up high) until it is completely warmed up. Thought choke but mechanic said it works properly. Thought vacuum leak but if you put your hand over the butterfly it will die, not continuing to get air and running. Any help would be appreciated.

[So Cal Mark]

the accelerator pump may be bad or the pump nozzle may be restricted. When the pump diaphragms leak, they can drain the float bowl causing long crank times when cold.
Does it bog on initial acceleration from a standing start? Completely covering the butterfly would test for a major vacuum leak, but you could have a small leak. Try gradually covering the carb throat and listen for rpm increases, or spray carb cleaner around the carb base, vacuum fittings and intake flange

[jc_wisconsin]

Thanks for your post Mark. After the long crank it bogs, sputters until warmed up or unless the RPMs are high. For instance, if I take off from a start I need to get the RPMs up fairly high for it to go smoothly. Anything less and it will sputter and jerk. Also if cold and I push the clutch in it will backfire unless I again keep the RPMs up, then it is smooth. When I first start it and it is struggling to stay running I pump it a lot. Then when it idles OK but rough I push on the accelerator and wait through a period of sputtering as the RPMs slowly rise. When the RPMs finally get higher it suddenly smooths out completely until I let the RPMs down. Does this help narrow?

[So Cal Mark]

it sounds like you have choke and/or accelerator pump issues, but it would be wise to also check the point gap and timing