January 23, 200916 yr Author comment_271866 I apologize for throwing in that rather moot comment. It was meant to be tonge-in-cheek not derisive. Actually, I'm only a proponent of EFI systems on vehicles that were originally equipped with it. Do you have access to a tool like a Uni-syn or Color Tune? I've used both of those in the past to assist in balancing carbs.no worries. I was a bit defensive there too. You have helped me quite a bit in the past with my EFI issues and has been appreciated.I have to pick up the uni-syn from motorsport... so far I was just trying to guage the flow based on what I was hearing.. Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271866 Share on other sites More sharing options...
January 23, 200916 yr Author comment_271869 Maybe the float bowls sits in different hights, still i think it is a adjustment problem, SU's are simple carbs and it seems that your front one is starving, so if there is no gasket leaks, i still vote for incorrect float hight..Do you understand the SU function?EFI the bastard:eek:ChrisHey Thanks.. I just saw the videos (2 parts). It seems that the float height may be the problem. I will re measure and adjust if necessary. Does this mean that the float level is lower than it should be? or higher than it should be.. I know it needs to be level to something in the bell housing or the nozzle?? Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271869 Share on other sites More sharing options...
January 23, 200916 yr comment_271871 As i understand it your float level is to low.Good luckChris Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271871 Share on other sites More sharing options...
January 23, 200916 yr comment_271873 ^^ I agree, sounds like the level is too low in front float. To test that, you could try to adjust the front nozzle down farther. You said they were both set at 2 1/2 turns down. Try turning the front only an additional 2 1/2 and see if that's any better. If it is, that would confirm that the level is too low. Don't leave it that way, correct the level so that both adjustments are similar (they don't need to be identical). Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271873 Share on other sites More sharing options...
January 23, 200916 yr comment_271876 Do you understand the SU function?EFI the bastard:eek:ChrisWhat's not to understand? Perhaps the simplest carb ever produced next to motorcycle carbs. Do you understand the EFI function? Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271876 Share on other sites More sharing options...
January 23, 200916 yr comment_271878 I don't understand this!What's not to understand? Perhaps the simplest carb ever produced next to motorcycle carbs. Do you understand the EFI function?What i meant was that if he undestand the simple function of SU's he would also know what is the problem, at least 80%, witch i think he do by now.And if it won't work he can always EFI the car.Chris Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271878 Share on other sites More sharing options...
January 23, 200916 yr comment_271888 Don't forget to check that both carbs are opening together. We've helped too many fight problems only the find out they failed to secure both carbs to the center linkage. Doesn't matter though cause you need new carbs anyway...... My standard friday afternoon answer..... Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271888 Share on other sites More sharing options...
January 24, 200916 yr comment_271889 I don't understand this!What i meant was that if he undestand the simple function of SU's he would also know what is the problem, at least 80%, witch i think he do by now.And if it won't work he can always EFI the car.ChrisMy apologies Chris. I thought those comments were directed at me. Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-271889 Share on other sites More sharing options...
January 25, 200916 yr comment_272002 No sweat Stephen Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-272002 Share on other sites More sharing options...
March 8, 200916 yr comment_276686 I have to say i have the same problem. Only it is reversed the back one causes the miss. I swapped the carbs and the problem seems to be gone. But i cant run like that no linkage. Ne ideas. Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-276686 Share on other sites More sharing options...
August 31, 200915 yr Author comment_293414 I have to bring this thread back as I am having issues with tuning my carbs. I originally had the float of my front carb set a 16mm and rear at 12mm as it is required for 1972s. Also, set the adjusting screw at 2 1/2 turns.However, the front 3 cylinders were not working. I then adjusted the front float level to 12mm. Set the adjusting screw 2 1/2 turns and still the same problem. BUT, when I set the screw at about 4 1/2 turns, the front 3 cylinders started working.I set the air flow using the synchronizing tool.What is the problem? Is the needle out of sync.? Please help. Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-293414 Share on other sites More sharing options...
August 31, 200915 yr comment_293416 I then adjusted the front float level to 12mm. Set the adjusting screw 2 1/2 turns and still the same problem. BUT, when I set the screw at about 4 1/2 turns, the front 3 cylinders started working.The front carb's float level is still too low. Correctly setting the level can be tricky for the inexperienced. You need to bring it up another 3-4 mm, as a WAG. Link to comment https://www.classiczcars.com/forums/topic/30578-cylinders-not-working-after-su-conversion/?&page=2#findComment-293416 Share on other sites More sharing options...
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