drftem Posted October 11, 2009 Share #1 Posted October 11, 2009 Ok I recently am being introduced to carbs. I have only owned fuel injected cars up to this point. I recently purchased a 74 260 with an l24 with su carbs. I found on the rear carb that the fuel line that ran from the float to the needle had a pin whole leak. So i replaced that vaccum looking line with some fuel line and well now the car has a horrible throttle response and idle. My assumption is the previous owner adjusted the carb to make it idle good without noticing the leak. Can I please find someone in the SanDiego area to help me adjust my carbs and teach me so I can do it myself next time?????? Link to comment Share on other sites More sharing options...
ChrisZ Posted October 11, 2009 Share #2 Posted October 11, 2009 First off, get hold of Ztherapy and get the right hose, only thing that will work, according to lot's of threads here.After replacing that hose, you can reach below each carb and find a little "button" that will lift the dome piston, if you lift the rear, the car will only run at the front carb, the idle should be rough, if it stalls you are to lean, if the RPM rises or continue to idle at the same RPM you are to rich, also get hold of a sync tool, you will need it.Chris Link to comment Share on other sites More sharing options...
drftem Posted October 11, 2009 Author Share #3 Posted October 11, 2009 awesome please someone else chime in. sorry not knocking your response id just prefer a second to your answer. Link to comment Share on other sites More sharing options...
Bonzi Lon Posted October 11, 2009 Share #4 Posted October 11, 2009 Call Ztherapy 503-587-9800 get two hoses and the 'Tune Up Video', may be on cd by now. Also get a sync tool, aka air flow meter, at the auto store.Personal experience: Newer carbs been sitting for 26 years. Never been in any carb in my life. Got the video, watched it twice. Removed carbs, did everything the video showed, had them back on and running great within 3 hours.Bonzi Lon Link to comment Share on other sites More sharing options...
70 Cam Guy Posted October 12, 2009 Share #5 Posted October 12, 2009 Also make sure your chokes are not sticking. If a nozzle gets stuck down this will cause some funny running. It won't idle very well, likely run very rich with black smoke, and generally kill the drivability.Did you remove the carb completely to replace the fuel line? They may be out of balance now if you did. I bought the Synchrometer from Motorsport Auto (MSA). It's an STI unit that's made in Germany. It's a very good unit. The carbs must be balanced at idle, and above idle (where the linkage takes over).I did a lot of reading here to improve my understanding of the SU's. By all accounts, the Ztherapy DVD is easily worth the 20 bucks. Link to comment Share on other sites More sharing options...
beandip Posted October 12, 2009 Share #6 Posted October 12, 2009 If you use the gas line from your parts store, it is too stiff and will cause the nozzle to bind and stick . When you use the choke to start when the engine is cold, lower than operating temp, the nozzle is drawn down. When you no longer need the choke to richen the fuel mixture and you push the lever forward , this is when the nozzle will stick. The same thing happens when the little hose becomes brittle and stiff from the heat on the exhaust manifold.Your Nissan dealer might have the correct hose , but for sure ZTherapy will. DO NOT USE VACUUM HOSE! It is not gas rated and will fail . Gary Link to comment Share on other sites More sharing options...
beandip Posted October 12, 2009 Share #7 Posted October 12, 2009 If you use the gas line from your parts store, it is too stiff and will cause the nozzle to bind and stick . When you use the choke to start when the engine is cold, lower than operating temp, the nozzle is drawn down. When you no longer need the choke to richen the fuel mixture and you push the lever forward , this is when the nozzle will stick. The same thing happens when the little hose becomes brittle and stiff from the heat on the exhaust manifold.Your Nissan dealer might have the correct hose , but for sure ZTherapy will. DO NOT USE VACUUM HOSE! It is not gas rated and will fail . Gary Link to comment Share on other sites More sharing options...
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