Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Carbon deposit

  1. #1
    Aspen and Volare Super Member 77superpak's Avatar
    Join Date
    Oct 2015
    Location
    Waukesha, WI
    Country:
    United States
    Posts
    510
    Thanks
    17
    Thanked 70 Times in 56 Posts

    Carbon deposit

    My slant 6 needs to run better. It'll start but a little smoke will come out the tail pipe until it's warmed up. It might need new valve guide seals but decided to take a look at the plugs. I'm running Champion plugs. All of them appear to be in the same condition. There is carbon build up on all of them. Each is gaped correctly. Would this likely be a timing issue?

  2. #2
    Aspen and Volare Super Member 77rr2x4s's Avatar
    Join Date
    Oct 2015
    Country:
    United States
    Posts
    1,183
    Thanks
    7
    Thanked 75 Times in 68 Posts
    Depends on whether they are black from being rich(gas) and if they are oil fouled. Have any pics of the plugs? What is the part number on the plugs? They may not be hot enough( heat range). Is the choke functioning correctly. If it is slow opening or not opening all the way it can make it run rich. The choke control is a common problem.
    Last edited by 77rr2x4s; 08-23-2018 at 04:15 PM.

  3. #3
    Aspen and Volare Super Member 77superpak's Avatar
    Join Date
    Oct 2015
    Location
    Waukesha, WI
    Country:
    United States
    Posts
    510
    Thanks
    17
    Thanked 70 Times in 56 Posts
    No pictures, I already cleaned them. I'll have to check the plug number. I used either Champion or Autolite. The choke could very well be the problem. When I installed it the wire broke. I'll have to make sure it's secured or replace it. Thanks.

  4. #4
    Aspen and Volare Super Moderator aspen79's Avatar
    Join Date
    Oct 2015
    Location
    Rib Mountain (Wausau) WI
    Country:
    United States
    Posts
    1,707
    Thanks
    2
    Thanked 178 Times in 140 Posts
    Black does indicate unburned fuel. Choke not opening all the way, improper jetting (unlikely on a stock engine), float set too high. Retarded ignition timing can also contribute due to not burning the fuel completely, or even a weak coil. Anything that causes the fuel to not fully burn will leave black deposits, which can be conductive and cause misfiring, even if you don't feel the misfire.

    This is just from personal experience, both on my own vehicles and at work. I've fixed many driveability issues by replacing Champion plugs with another brand, even if the Champions were brand new. Autolite, Motorcraft, AC Delco are all good plugs, along with NGK and Denso also. There's something not quite right about Champions construction whether it's the insulator material, the electrodes, who knows.
    1979 Aspen Sunrise 500". Bought in 1987 with 72,000 miles and a mighty E24 California emission 90hp leaning tower of power/4-speed
    1996 Dakota with a torque monster (not) 3.9L V-6 and automatic owned since 1998. Now demoted to winter duty
    2008 Ford Mustang V6, the new summer daily driver

  5. #5
    Aspen and Volare Super Member 77rr2x4s's Avatar
    Join Date
    Oct 2015
    Country:
    United States
    Posts
    1,183
    Thanks
    7
    Thanked 75 Times in 68 Posts
    Years ago when I worked at a dealer and a car would come in not running right. First thing they checked was what spark plugs were in the car. If it had AC plugs in it they would change them out. For some reason the old mopars wouldn`t run right on AC plugs. I have had good luck with champions and i have used autolites too. Sometimes when the plugs are cross referenced to a different brand the heat range plug they give you may not be correct for your car.
    Last edited by 77rr2x4s; 08-23-2018 at 08:05 PM.

  6. #6
    Aspen and Volare Super Member 77superpak's Avatar
    Join Date
    Oct 2015
    Location
    Waukesha, WI
    Country:
    United States
    Posts
    510
    Thanks
    17
    Thanked 70 Times in 56 Posts
    Thanks guys. What is the part called that bolts to the manifold to operate the choke? Is it the choke thermostat? That is the part that has the wire broken off it. I don't think it's a coil issue. A brand new one was put in not too long ago. I do have an Accel coil sitting on the shelf I could install. Going to try and put the timing light on it this weekend to see where it's set at and get some new plugs.

  7. #7
    Aspen and Volare Super Member 77rr2x4s's Avatar
    Join Date
    Oct 2015
    Country:
    United States
    Posts
    1,183
    Thanks
    7
    Thanked 75 Times in 68 Posts
    1977 slant six champion plug should be a RBL15Y according to the book

  8. #8
    Aspen and Volare Super Member 77rr2x4s's Avatar
    Join Date
    Oct 2015
    Country:
    United States
    Posts
    1,183
    Thanks
    7
    Thanked 75 Times in 68 Posts
    Yes, it is the choke thermostat and there should be a choke control connected to it also The part numbers for the choke thermostat in 1977 is 4027705 for 1 bbl , 4027707 for 2 bbl
    Last edited by 77rr2x4s; 08-24-2018 at 10:55 AM.

  9. #9
    Aspen and Volare Super Member 77rr2x4s's Avatar
    Join Date
    Oct 2015
    Country:
    United States
    Posts
    1,183
    Thanks
    7
    Thanked 75 Times in 68 Posts
    If you can`t find one local ebay has them. Here is a 2 bbl one. https://www.ebay.com/itm/Carburetor-...d=331604376466

  10. #10
    Aspen and Volare Administrator White Aspen R/T's Avatar
    Join Date
    Oct 2015
    Location
    Jackson, Missouri
    Country:
    United States
    Posts
    2,505
    Thanks
    283
    Thanked 179 Times in 150 Posts
    Blog Entries
    6
    Try some cleaner in your gas.
    AspenandVolare Administrator

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •