Guest BadKarmaCreepin Posted October 21, 2002 Share Posted October 21, 2002 so it's getting more often now, i pull in to park the car, shut it off, and it keeps trying to run. it's getting really annoying. i don't know if it's the timing or the carbs. anyone have any ideas? there is an awful lot of exhaust and odors, so i'm thinking it's the mix. although it is a straight pipe with no converters...suggestions? Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 21, 2002 Share Posted October 21, 2002 Probably running a little rich. Check timing too. What needles do the carbs have? I have SM and N47 I think, and the SM's are alot richer. I have an easier time getting it to run properly with the stock type needles, but need to work the the SM one's. Maybe an MSD would help. Quote Link to comment Share on other sites More sharing options...
Sumo Posted October 21, 2002 Share Posted October 21, 2002 With my car it diesel'd because of the mixture. It was running too rich, so i turned the mixture screws in clockwise then as soon as the idle got a little rough i backed it out a half a turn. The timing was only a degree advanced and the idle was on spec. Although a year later i had to have the carb rebuilt anyway. Quote Link to comment Share on other sites More sharing options...
Guest Zachb55 Posted October 22, 2002 Share Posted October 22, 2002 also take to heart the fact that you may be using way too low octane fuel, maybe trying a higher octane like 87 or even 91+ and this might fix the problem, since a lower octane fuel can ignite itself and this can even lead to preignition and serious engine problems, like holes in your pistons, and thats not good. -Zach Quote Link to comment Share on other sites More sharing options...
DAW Posted October 22, 2002 Share Posted October 22, 2002 What is the idle rpm? Does it seem to be working to crank when it's hot? DAW Quote Link to comment Share on other sites More sharing options...
Guest BadKarmaCreepin Posted October 22, 2002 Share Posted October 22, 2002 it's idling at about 1200-1300 when it's warm, 800 when it's cold. i used 92+ octane on the trip back from FL, but then last week switched to 87-89 octane. i guess that could be the problem. on the SU's, i have a book that tells me where the mix adjustment bolts are, but they're saying twist 'em clockwise until the car stalls , then go between 1/4 and 1/2 a turn counter-clockwise. for the front 3 cylinders, then the back 3. sound good? also, should i try messing with the timing with out a light? i really don't want to mess it up and destroy the engine..... Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 22, 2002 Share Posted October 22, 2002 Idle is wayyy to high, you're probably off the idle circuit and on the mains. Should idle at about 750-800 warm. Choke will take care of cold idle. Have you sync'ed the carbs? Tim Quote Link to comment Share on other sites More sharing options...
Guest BadKarmaCreepin Posted October 22, 2002 Share Posted October 22, 2002 ok, so how do i lower the idle? and, is the high idle causing the dieseling? thanks. edit: and how do i synchronize the carbs? i've never worked with 2 before, let alone 1 on a side note, i did fix that starter problem thing, i'm so proud! Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 22, 2002 Share Posted October 22, 2002 You need to get a balance tool to make sure that both carbs are flowing the same air (vacuum). Need a sync tool for that. That is a basic piece of equipment needed to tune dual carbs. Without it, you really can't do anything, because you just don't know how each carb is working. You can get one from Victoria British, or JCWitney etc. Tim Quote Link to comment Share on other sites More sharing options...
Guest BadKarmaCreepin Posted October 22, 2002 Share Posted October 22, 2002 is that the little round metal hing with a bar and a bubble in it that rotates? if so, i have one of those.... Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 23, 2002 Share Posted October 23, 2002 That's it, Have you balanced the carbs? TIm Quote Link to comment Share on other sites More sharing options...
Guest BadKarmaCreepin Posted October 23, 2002 Share Posted October 23, 2002 ok, well i tried tuning them last night. i didn't mess with the air flow at all. i evened out the balance screws and adjusted the idle screws to get it idling at about 800 rpm. then i shut off the engine, closed the mixture knobs underneath, and equally turned them out 2 1/2 turns (per instructions found online according to altitude and temperature). i still get a little diesling every know and then, but it's not the 15 seconds of running, more like 1/2 second. so i think it might just be the 88 octane in the tank. good job or no? let me know! Quote Link to comment Share on other sites More sharing options...
DAW Posted October 23, 2002 Share Posted October 23, 2002 It sounds like the idle mixture was off or unbalanced. Get rid of the low octane gas, put a Uni-Syn on the carbs to confirm the airflow is balanced both at cruising rpm and at idle. My experience has been that since the idle mixture adjusters set the height of the main jet which affects the entire rpm range mixture, it's best to have these close to symmetrical, even if the idle initially feels a bit rough, rather than to spend a long time trying to balance the idle mixture where one jet may end up higher than the other. DAW Quote Link to comment Share on other sites More sharing options...
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