One spark plug Burns black

35

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

111,075

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

Volvo P1800 Experts

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

Related Models For Sale

Used Volvo 122
3 listings
Used Porsche 911
142 Great Deals out of 5,020 listings starting at $10,850
Used Jaguar E-TYPE
32 listings
Used Chevrolet Corvette
178 Great Deals out of 19,858 listings starting at $2,490
Used BMW 2002
8 listings

Used Cars For Sale

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.