I initially noticed a lot of carbon build-up on my sparkplugs about three months ago. I have since rebuilt the head and I am still having the problem (Plugs get black right away) It does not appear to be oil, and I have not noticed any blue smoke from my exhaust. The car runs rough, especially when it is cold (very choppy acceleration and the weber carb backfires). Where should I look to remedy the problem?

Thanks again,

Chris (68 142S)

And on top of what the others have said, what plugs are you using? What are they gapped to?
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Kyle - '68 142? - Oregon Volvo Tuners?

I am using NGK plugs (not sure the letter designation). They are the ones recommended for the B20 engines, gapped at .030"

Call me crazy, but the backfiring thru the carb sounds like a timing issue to me. You may want to check that as well. Improper timing can also cause improber burning of the fuel mixture which can lead to soot on the plugs. I have very little experiance with Weber carbs, so this may or may not be relevant. But its certainly worth looking into.

Soot = over-rich mixture...too much gas.
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MPergiel, Elmhurst, IL '74 145e T-5 'Orange Alert'

1) Check fuel pressure. A Weber likes 4 psi; any more will pump raw gas out the jets.

2) Check float level on the Weber.

3) Put the right jets in the Weber for your motor. They don't come pre-tuned.

Thanks for the info.
How might I check the fuel pump pressure. If I am getting too much fuel from the stock fuel pump, is there any fuel regulator I can buy for this set-up.

Thanks again,

Chris

You can get a hand-held fuel pressure gauge in most auto parts stores. It hooks into the fuel line between the pump and the carb.

The original pumps don't put out too much pressure, but I've certainly seen replacements that do. You can get an inline adjustable regulator at many parts places -- certainly any place that has a performance parts section.