Guest Anonymous Posted April 1, 2002 Share Posted April 1, 2002 Kinda dumb question but the choke is when the butterflys are closed right? And can someone show me a picture of how the choke cables are supposed to be attached? Quote Link to comment Share on other sites More sharing options...
jimzdat Posted April 1, 2002 Share Posted April 1, 2002 If you've got the original "flat top" carbs, then yes, when you pull the choke lever, the butterfly should close. As far as the pic for the cable, sorry--I put earlier carbs on mine. If you're not worried about originality, I would check ebay for a set of 70-72 carbs--they will fix 99.99% of the problems you are having, and you can usually find a set for under $200 Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 1, 2002 Share Posted April 1, 2002 I have the 70-72 carbs on there Got a pic of those? Quote Link to comment Share on other sites More sharing options...
Mike C Posted April 2, 2002 Share Posted April 2, 2002 The SU (Round top) don't have a choke per se. The definitely don't have a butterfly. When you choke an SU, you are just lowering the main jet which allows more fuel to flow by at idle. When you take the choke off, it just pushes the jet back to its zero setting. If your choke is sticking, push the lever off, open the hood and push up on the bottom of the carb. If the tube moves in, it is sticking, if it is firm, it is not. Quote Link to comment Share on other sites More sharing options...
Guest James 72 240Z Posted April 8, 2002 Share Posted April 8, 2002 The SUs do indeed have a butterfly. This butterfly is opened by your throttle linkage and controls the air drawn through the carb. The choke linkage, while responsible for lowering the jet nozzle and therefore richening the mixture, also pushes the main butterfly open a crack. You should make sure that the choke cable draws down each jet nozzle an equal distance and also that your choke linkage opens each butterfly the same amount. You can adjust the choke/butterfly action by straightening or bending the bar from the choke lever to the butterfly. Unfortunately, you really should take the carbs off to see the choke/butterfly action properly. If you really want to understand the SU carb get yourself the ZTherapy video (http://www.ztherapy.com). I just rebuilt my carbs using it...very helpful and only $20. Quote Link to comment Share on other sites More sharing options...
Mike C Posted April 9, 2002 Share Posted April 9, 2002 Oops! You're right James. I forgot that, and I've probably rebuilt 6 sets of SU! Looking down the front I forget they're on the back... Quote Link to comment Share on other sites More sharing options...
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