[T2] Running rich in #2 only

[Christopher Slaymaker]

This has been going on for some time.  My bus has had declining MPG. 

I installed this mexi-motor back in 2006. It seems the MPG took a hit when I installed a stock muffler in 2011. Prior to that, I had a Thunderbird extractor. 

In any case, ever since the MPG declined from 18 to 14, the #2 spark plug has always been black  while the others have been kinda mocha colored (except #3, which typically runs hotter and is lighter colored). 

Now I’m starting to go through more oil between changes, and I figure that #2 cylinder is probably the reason (the rings are taking a beating with excess fuel in that cylinder).

I will soon be doing a top end rebuild (70,000 miles), and I think a new center manifold piece may be in order (one of the risers has a hole burnt in it which I have patched with a hose clamp).

How does only one cylinder burn rich?

Chris Slaymaker
1971 Westy “Lurch”
1971 Squareback “Foster”

“At least I’m enjoying the ride"