Ok, so right now I'm out trying to sync the carbs. It's not easy and this is my first time. I have a fan blowing on the engine and headers.
First, I notice that the #4 muffler is very hot. Even the very tip of the muffler will sizzle saliva on your finger. The rest are warm but won't kill you.
Until you complete the vacuum sync, its more or less :normal: for some cylinders to get hotter than others. Syncing is to make them work equally.
Second, at about 2k rpm the #2 carb is a little low and it's hard compensate for it with the other three.
#2 is not adjustable on stock PD carbs. You MUST match whatever vacuum noted on #2 to each of the others in turn.
It's still revving up to about 3k rpm every so often and when it does the #2 then shoots up. It it normal for it to go out of sync when it's revved?
No, it is not. They will all rise and fall in unison when sync is achieved.
Should I keep trying to sync them like this or start looking at other things?
Perhaps investigate those IMS deviations noted below. Some problems will make sync impossible.
90 mains, 42 slows, needle clip position 2nd from top
This should be 3rd from top for stock position
and IMS were all 1.25 turns from fully closed. I forgot to mention that I set them to 1.5 turns out as the manual states.
This may not be open enough for the UNI filter change. Go to two turns or even 2.5 until you finish the vacuum sync.
Now I remember that one of the IMS tips was slightly bent. He must have screwed it in too tightly. I have a sneaking suspicion that it's the #4...the one who's muffler is piping hot.
This is of some concern, a bent needle or one that was overtightened can damage the carb body where the needle tip inserts, as it is a jet orifice. I've seen some carbs where the tip was broken off and jammed into the metering hole. Others had the hole widened. This is the pilot circuit supply which dominates idle mixture. If plugged, no mixture is delivered and certainly no vacuum sync is going to be possible with a carb so damaged.
If the hole has been made larger, the adjustment position will not be the same as the other anymore and counting turns will not not work. There is another method for IMS adjustment, but it's a bit fiddley.
