Different colored spark plugs
Melting Slicks
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
Try different settings on idle mixture, for giggles.
I have dual quads. 8 mix settings took a while got it correct.
Does the Roughness change as engine gets hot?
I also had Gas boiling problems before i had a Bypass regulator installed, caused rough idle.
I have dual quads. 8 mix settings took a while got it correct.
Does the Roughness change as engine gets hot?
I also had Gas boiling problems before i had a Bypass regulator installed, caused rough idle.
Thread Starter
Advanced
Joined: Aug 2015
Posts: 55
Likes: 1
From: Hanover PA
No joy. It does smooth out at 14, but then starts to backfire out of the carb. I replaced the other two plug wires, but still no change. It almost sounds like an intermittent misfire. So, to summarize here is what I have done so far.
Replaced plugs/wires
Adjusted float level
Replaced cap/rotor
Replaced intake gaskets
Adjusted carb to 1 1/4 turns on both sides
Replaced PCV valve
Set timing to 12
Checked vacuum and staying steady at 18"
Checked vacuum advance
Not sure what else to try at this point. It fires right up every time.
Replaced plugs/wires
Adjusted float level
Replaced cap/rotor
Replaced intake gaskets
Adjusted carb to 1 1/4 turns on both sides
Replaced PCV valve
Set timing to 12
Checked vacuum and staying steady at 18"
Checked vacuum advance
Not sure what else to try at this point. It fires right up every time.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
If the outer ring on your damper has slipped into a retarded position when you time it to 14 BTDC it could actually be a lot more like 25 to 30 degrees and that would certainly make it backfire. If your damper is the original it needs replacing for sure because those old dampers don't last forever. The silicon-type rubber in the new dampers is injected between the outer ring and inner hub and forms a permanent bond.
When I was assembling my 454" with it standing on its rear end I put my damper onto the end of the crankshaft and gently tapped on it and the outer ring literally FELL down onto the timing chain cover. As in CLUNK. So there's every possibility your outer ring has slipped into a retarded position and its way too far advanced.
When I was assembling my 454" with it standing on its rear end I put my damper onto the end of the crankshaft and gently tapped on it and the outer ring literally FELL down onto the timing chain cover. As in CLUNK. So there's every possibility your outer ring has slipped into a retarded position and its way too far advanced.
