idle problems

[burnt_orange_720]

Hey new to the forum but yeah
i just bout a 83 datsun 720 complety bone stock and everything bought it and was driving fine then the weather change so i had to change turn the screw on the car to keep it running and ran fine for awhile but just recenctly yestarday it died on me when i pushed in the clutch i thought maybe i had the screw in the wrong place so i turned it again and it idle and everything but it also now goes up through the rpms like i have a leak or something im not sure but today i turned the idle down but not alot and it feel like one i have alot of hesitation causing my truck to jerk if i dont feather the peadal i dont know what to do anymore
if anyone could give me some lead way it would be greatly appricated

[fastboatman29212]

Welcome to the 720 forum on NICO!

Tell us how many miles are on your truck and throw up some pix too.

Your problem could be one of several things. It is probably a carb problem - or vacuum line leak - or spark and ignition issue - or a combination of all 3.

1. First decide if you want to keep the stock carb or switch to a Weber aftermarket. It will depend on your states emissions laws but many members here like the Weber carbs.

If you decide to switch to a Weber carb, then that will eliminate almost all of the vacuum lines - so you could skip step 2 since you would not need to replace them if you get a Weber carb.

2. If you decide to keep your stock carb like I did, then I'd recommend that you replace all the vacuum lines. You'll need about 30 feet total. There are several different sizes with different inside diameters.

See this post - vacuum-lines-completely-replaced-wow-t506342.html

3. New spark plugs and wires and distributor cap and rotor will help too.

That should be enough to get you started. Adjusting the idle screw is not likely gonna get you what you want in the end.
You might need to rebuild the carb later, but these other things are more likely to get you running again.

[lambohaha]

Just to reiterate what fastboatman just said the vacuum lines could be the culprit. I`ve been finding cracked and busted ones along and along. I should`ve replaced them all at once but I didn`t so now I`m doing them as I find them. It seems the older ones are becoming more noticeable the more I drive it. The under hood heat is taking its toll on the older ones.
It`ll run fine for a while then all of a sudden it goes to junk. I`ll find a bad vac line, replace it then back to running good again until the next vac line cracks lol.

[flinterman2000]

Yeah, check the vacuum hoses and spray the carb with a good cleaner.