Bad harmonic balancer symptoms?

[Clone TIE Pilot]

I have been having a rough idle I just can't get rid of. Checked under the car and saw the rubber inside the balancer is all dry cracked,mI can even flake some off with my fingernail. As far as Iknow it the original balancer for the engine, a 86 L69 305. Everything else seems to check out ok.

 

[Vilanus]

If the rubber looks bad replace it. For the rough idle, check for vaccum leaks, spark plugs, wires, cap, egr if equipped, carb tuning, timing, compression, converter...

 

[Clone TIE Pilot]

I smoked the engine and there are no vacuum leaks, spark plugs and O2 sensor are new, EGR valve is ok, carb is set to factory specs and I can get the correct dwell despite the rough idle. Supposedly a bad balancer can mimic a misfire by causing uneven RPMs.

 

[bruisedbanana79]

I agree that if its looking that bad just replace it and see it that remedies your problem. if you dont have a puller and installer tool you can always rent them from autozone.

 

[bracketchev1221]

Even though the rubber is bad, unless you can see it wobbling its not the cause of a rough idle. Its a neutrally balanced balancer, meaning it can spin on the hub and still be balanced.

 

[bruisedbanana79]

I smoked the engine and there are no vacuum leaks, spark plugs and O2 sensor are new, EGR valve is ok, carb is set to factory specs and I can get the correct dwell despite the rough idle. Supposedly a bad balancer can mimic a misfire by causing uneven RPMs.

Did this rough idle appear out of no where? I think a little more history leading up to the problem might help us identify the problem.

 

[Clone TIE Pilot]

It just popped up out of nowhere. The EGR valve holds vacuum, no trouble codes, good compression, etc.

 

[fleming442]

Just a stupid thought: it's been wet here in the Mid-Atlantic, so maybe hose the inside of the distributor cap with some WD-40?

 

[bruisedbanana79]

Is your choke fully opening once warmed up?

 

[lilbowtie]

Google it - see if the shoe fits.