Re: [Amc-list] Rambler won't idle right

[Matt Haas <mhaas@xxxxxxx>]

You most likely have a vacuum leak between the intake manifold and head. 
The only fix is to remove the manifolds, separate them, and reinstall 
them. AMC issued a TSB on this problem. You can read about it at 
http://www.mattsoldcars.com/RestoreAmerican/loose_intake.shtml (this 
page is based on the TSB, my notes and the TSB's torque spec). When they 
are out, have the manifold to cylinder head surface checked to see if 
it's warped. Also, when you get the new gasket set, it will have an 
extra gasket in it that is supposed to be used to help seal the exhaust 
but if the manifolds are warped, it isn't needed (the factory just used 
an intake gasket).

BTW, my 68 American had this same problem and it drove me nuts until I 
found out about the TSB. I was also never able to find a vacuum leak 
until I had it run rough pulling into my driveway after it was running 
good. Spraying the area where the manifold mates to the head with WD-40 
smoothed the idle out pretty well but it didn't do didly unless the 
engine was really hot and already running badly.

As far as adjusting the carb goes, use the method in the TSM (note that 
you need to adjust points, timing -- adjust at 500 RPM with vacuum 
advanced line disconnected and plugged, and idle speed first -- 600 RPM, 
A/C on if you have it). That way is to slowly richen the fuel mixture 
until idle speed starts to drop off. Then, slowly lean the mixture out 
until you reach max idle speed and continue leaning it out until idle 
speed drops off again. Finally, slowly richen the mixture until max idle 
speed is regained. If you end up more than 50 RPM higher than where you 
started (i.e. anything over 650 RPM), reset the idle RPM to 600 and 
start again.

Matt

On 7/26/2008 4:33 PM, Thomas Garner spouted this sage advice:
> Hey guys,
>  Got another problem with my 64 Rambler Classic. (232 engine)
> It's actually been a problem for a while.
> 
>  First, on the recommendation from somebody on this list, I plugged off the vacuum line that is between the two back cylinders and ran everything off the vacuum hole in the center, below the carburetor. (I think this helped)
>  
>  I have a friend (older shade tree mechanic fellow)who helped me adjust the timing and then the carburetor. He gets it to idle perfectly. (He adjusts the carb, then goes back to the exhaust pipe and listens for sputter, then he adjusts and listens, etc, etc. He keeps doing this till there is no sputter from the tail pipe) 
>  Then I take it down the road and get it up to speed. After running it for a while, I notice that pulling up to a stop sign or red light, it is no longer idling smooth. It's seems to be missing and sputtering pretty bad at times. It's not consistent either. Pull up to a light and it might idle fine and then the next light it might idle rough and the next one a little rougher and the next one be fine again. I take it back and he adjusts the carb again until it runs smooth and then it does it all over again.
>  We ran through the entire engine looking for vacuum leaks, checking compression while hot and cold, new points, plugs, wires, cap, rotor and making sure the carb is good. (Two rebuilt carbs, one from Advanced and one from Ebay.)
>  
>  Neither he nor I are pro mechanics and are not certain why it's doing this. 
>  He believes it may be a problem with the vacuum advance on the distributor, but he's not sure.
>  Any ideas on what may be causing this?
> 
> FREE SATELLITE DISH AND INSTALL!!
> http://www.bestofdishnetwork.com/
> 
> 
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-- 
mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1967 Rambler American wagon
1968 Rambler American sedan
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