My 82 4x4 wagon 4 speed sputters after I turn it off then finally shuts off. I had the timing adjusted at the shop and it still makes this embarrassing noise. What is it and how do I fix it????

Dieseling. Yeah, it's embarrassing. The cause is simple. There is something in the combustion chamber that is hot enough to act like a spark plug, igniting fuel even with no spark. Usually, carbon in the combustion chamber does it, but sometimes it's something like the spark plugs' ground electrode. Especially if they are worn and the electrode is real thin. Without going to the root problem, you might be able to keep it down by changing the plugs (if it hasn't been done in a while), or by running a top cleaner. You can use sea foam, I know that GM makes a superb top cleaner. There are other aftermarket brands. Basically, you take the air cleaner off, pour this stuff in slowly while keeping the engine running, and then just dumping it in until the engine dies. Let it sit for 15 min. and start her up. This dissolves most of the carbon.

 

As for root causes, the most common are 1. Idle speed set too high, 2. Engine running too hot, 3. poor fuel quality 4. It's actually a ford 300 six-cylinder you are working on

 

Having the ignition timing advanced too far will also raise combustion temps, and will get that carbon glowing.

 

Well, that's all I can think of right now.

I believe you're talking about after-run or dieseling where the engine continues to run after turning off the ignition. The only thing I can think of that could be wrong is that your anti-diesel valve has stopped working. It's the big hex shape part on the front of the carburetor with a wire sticking out of it.

Well, one more thing. Some carbs (and I don't actually OWN a sube, so I don't know) have a fuel shutoff valve that snaps shut when the ignition is turned off. Without fuel, it won't diesel. If this imaginary valve is on all the time, it will aggrevate your problem.

I believe the Carter-Webber carb she has is different as far as the location of the anti-dieseling solenoid. if there is one, it's not upfront like our wonderfule (NOT) hitachis.... but definitely a good spot to start....

Thank you guys. I'll try the top cleaner first because I just replaced the plugs and wires. :-p