One spark plug Burns black

45

Asked by Jan 06, 2017 at 12:19 AM about the 1967 Volvo P1800

Question type: Maintenance & Repair

B18 engine completely
restored running twin
Mikuni carburetors first
spark plug nearest the
radiator burns black all the
rest are chocolate brown
why

1 Answer

124,415

Overly rich fuel/air mixture, dirty air filter, too much driving at low speeds, or idling for a long time. Switch to “hotter” plug. (The higher the plug number, the hotter the plug.) Oil-fouled plug. Wet, black, oily deposits on insulator tip and electrodes.

Your Answer:

Shortcuts

Volvo P1800 Experts

  • #1
    chassy
    Reputation
    110
  • #1
    Richard Boettger
    Reputation
    110
  • #3
    Michael Kane
    Reputation
    60
View All

Related Models For Sale

Used Chevrolet Corvette
10 Great Deals out of 523 listings starting at $7,995
Used Ford Mustang
35 Great Deals out of 1,236 listings starting at $3,995
Used Chevrolet Camaro
9 Great Deals out of 946 listings starting at $11,500
Used Porsche 911
12 Great Deals out of 252 listings starting at $15,945

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.