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Restoring - General discussions that span across many different groups of years and models => Drivetrain => Topic started by: tvtommy on August 11, 2016, 11:48:52 AM

Title: I6 200 rough idle...
Post by: tvtommy on August 11, 2016, 11:48:52 AM
Good morning and thanks for reading....

Does anyone know if the is a cure/fix for the rough idle common to the 200 I6 motors?

I've read that multi carb setups can cure this, but I don't want to lose my original setup.

Thoughts?

Tommy
Title: Re: I6 200 rough idle...
Post by: jwc66k on August 11, 2016, 07:33:13 PM
What year? Smog equipment can create problems. So can a bad valve, an old spark plug wire or a carburetor needing a rebuild.
Jim
Title: Re: I6 200 rough idle...
Post by: WT8095 on August 11, 2016, 11:06:51 PM
Start by checking for air leaks, especially around the throttle shaft.
Title: Re: I6 200 rough idle...
Post by: tvtommy on August 12, 2016, 12:41:53 AM
'67

Had a vacuum gauge on her today, shes solid at 20in, and has an occasional dip on the misses shes experiencing.
Title: Re: I6 200 rough idle...
Post by: MattDoscher on August 12, 2016, 09:11:31 AM
20" of vacuum is real good.  The higher your vacuum the better off you are.  I would double check all 6 spark plugs and their gaps, the condition of the points and their gap (assuming you still have points on it), plug wire condition, distributor cap terminal condition.  All straight 6's have a certain amount of shake to them mostly attributed to the long intake log and a 1bbl carburetor having to feed properly atomized fuel all the way to cylinders 1 and 6.  You can play around w/ your idle speed and fuel/air mixture too to smooth it out.

Matt
Title: Re: I6 200 rough idle...
Post by: 67gtasanjose on August 12, 2016, 01:53:07 PM
Varying ignition points dwell angle (as seen with an analog dwell meter) could do the same thing. Usual suspect is worn bushings in the distributor (verified by removing cap and pulling around on the rotor)
Title: Re: I6 200 rough idle...
Post by: tvtommy on August 12, 2016, 08:11:05 PM
Looks like I have a few things to do this weekend =)