choke issues / engine swap question

[JohnnyRaggs]

Hey all, trying to get my '71 spider running properly. Have rebuilt the carb and it runs quite well, but when the choke is pushed in (choke plates fully open) the engine stalls. With the choke cable slightly pulled out it runs decent. I also notice that when the engine is warm the rpm's seem to hunt a little. #4 cyl has lower compression then the other 3, but its not totally dead. Anyone have any info on this? I just want to have it running well for the summer as I plan on re-building the engine/swap engine in the winter. That being said, as i currently have the 1400 in, what would you all recomend for a good swap for more power and fun.

[baltobernie]

It's possible that you have a vacuum leak, and enriching the mixture with a little choke makes up for it somewhat. When the engine is warm, perhaps you're feeling a "lean miss" from that leak. A cheap & dirty check can be done with an aerosol can of carb cleaner, with tube nozzle. With the engine running rough, systematically squirt small areas around the carb base, hose nipples, etc. one at a time and see if the engine smooths out at any point. If so, there's your leak. Don't incinerate your car, yourself, or your house.

[JohnnyRaggs]

Ya, I thought that may be the cause. I will check that this weekend. I did incinerate myself once when I was apprenticing at BMW. I was working on a older E30 3 series, looking for a vac leak with brake clean, turns out it also had a arcing spark plug wire. Needless to say there was a nice fireball and some eye brows missing.

[majicwrench]

You need to make sure the idle circuit is clear. Pull the adjusting screw AND pull the idle jet, it is behind a brass screw which faces out towards the fender, up towards the top of the carb. My 72 plugs that jet on a farily regular basis, and then won't idle. ANyway, piss a little carb cleaner in the passages and blow with compressed air. Safety glasses?? Then blow out jet, reassemble.
Pissing carb cleaner around is not my fav way of finding leaks, is a good way of losing eyebrows and making a real mess. Carb cleaner vapors will get sucked down carb throat and idle will pick up no matter where you spray it. Stephascope you can hear leak, is safe.
Keith