SLO RDE

Hey,Well heres the next problem as the title says it keeps sputtering when I turn it off.Is that a timing issue or fuel ?I think it's a timing thing myself.I just recalled most of the time I run the mid octane gas but right now and since this has been happening it's got low octane gas in it.It doesn't Knock when Its running, thanks for any ideas I don't want to mess with timing unless I have to Thanks, Dale

Mikes80L48

Last time mine sputtered when I shut it off it chewed half of the teeth off of the timing chain gear. Ever since that was replaced it hasn't sputtered once.

lars

SLO -
Drop your idle speed down just a tad. Chevy had a problem with this issue, and the Service Bulletin that was issued instructed dealers to simply lower idle speed about 50 rpm.

GR8T WYT

Sounds like timing, reducing your idle by 50 RPM won't do much unless your engine idles at about a grand or better. carbon build up in the heads can cause hot spots and run-on after you shut down. For what it's worth. Bob

PatG

Mine does that if I run any other than 93 octane but my engine is modified with about 9.7:1 compression.

Vetterodder

:iagree:

While other factors such as too little advance or hot spots can cause run-on by themselves, a high idle speed can make the problem worse and, often as not, a high idle speed is the problem. The faster an engine is turning the more momentum it has and the longer it will want to keep turning at shut down. Before electronics allowed lower idle speeds, mfg's resorted to raising idle speeds to clean up emissions and also to compensate for a poorer idle caused by emission controls and calibrations. The early smog engines resorted to leaner mixtures and less timing which created a favorable condition for run-on. Combined with the added momemtum from higher idle speeds, engines didn't want to stop. With manual transmission cars you could let the clutch out a little with the brake on to slow the engine a little at shut down.

Matt Gruber

always shut it off in gear :nopity

Sun King

A) timing is too far advanced
B) idle speed too high

Try cleaning up the linkage around your carb first. Then slow down the idle. If you need to, check your timing w/a light and adjust 2' at a time.

carlmb

Are you running an MSD box by any chance? Had same problem til I installed diode as recommended by MSD.

LFZ

stick with the higher octane gas....had the same problem with my chevelle. :thumbs:

Vetterodder

Actually, more advance creates more resistance to rotation by trying to push the piston back down. Too little advance though can increase engine temps which in turn contributes to "dieseling".

Jvette73

As well as the other suggestions Ill also support Mikes80L48 statement of possible worn timing chain causing late valve timing and excessive cylinder heat which can cause hot spots. So when you shut off the ignition, the hot spots are still glowing red hot enough to continue providing ignition source for the engine, hence the motor runs on. shutting it off in gear can help make it quit running. I too once had a Olds V8 that ran on bad. evevtually the timing chain gave out and the car wouldnt start. When the timing chain was replaced the never ran on after that.