1981 chevy 250 inline 6, Idle problems

I have a 250 inline 6 that is not running good. It cannot idle for any period of time. As though there was a problem with the Carb. The Carb seems to be clean and in working order. I did notice what i thought to be excessive Emissions vaccum lines on the top of the motor. What exactly do these lines pertain to, would it be whats effecting my performance, and what would be the result if I removed these lines? any help would be GREATLY appreciated. Thank You for your time.

Reply to
CulliganMan
Loading thread data ...

Reply to
none2u

memory says the carb body to base screws like to come loose, and also the carb to manifold mounting nuts, and or gasket shrinkage.. Grasp the carb and gently try to twist it to and fro, if there is movement between the body and the base the screws are loose, and you get internal vacuum leaks. The carb has to come off to get to the screws. check to make sure the two 1/2 nuts holding the carb to the manifold are snug, they don't have to be king kong tight. if they are loose again you get a vacuum leak. As none2u said those years had a ton of vacuum lines, if they are old and cracked that can cause all kinds of problems. Be very careful of any "thermal" vacuum switches on the manifold, with age the "tees" get brittle

Whitelightning

Reply to
Whitelightning

Reply to
Frank S.

In addition to the good advice you've received you can also check for vacuum leaks by getting a can of starter fluid and spray a quick shot at different locations suspected for leaks and if the idle speeds up you have found a leak.Spray the base of the carb too but be aware that some overspray will get to the incoming airstream and make the idle go up a bit even if there is no leak.course you'll probably need to turn up the idle speed first is it can't idle as it is.(little screw at the trottle stop,side of carb) You may even hear a leak hissing away. listen carefully.

Reply to
brianorion

Very very bad advice. Ether ignites very easy, that's why it works so well as a starting fluid, and since the intake is over the exhaust manifold this is a good way to turn you truck into a bar-b-que grill. You can do the same thing with a spray bottle of water, or a can of WD40 which does not burn any where near as easy as ether does.

Whitelightning

Reply to
Whitelightning

Reply to
brianorion

good point.Actually I use wd40 (wth was I thinking?)

Reply to
brianorion

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.