Is this too rich?

Discussion in 'Mech Tech' started by Fronkjunior, Apr 5, 2020.

  1. Hi all, I have read a few posts regarding fuel mixture and I seem to be running rich according to the colour of my plugs. I gather that a bit rich is no big deal, but it this too rich (see photo)? If so, is there a DIY solution? I have probably done 2000 miles on these plugs and it starts and runs well. I have a 1700cc engine with a recently refurbed pair of Solex carbs.

    Thanks for your help.

    Ade
     

    Attached Files:

    Last edited: Apr 5, 2020
  2. Seen worse on my Bug, but definitely a touch on the rich side. A little bit rich helps cooling :) others might be along to diagnose, and possibly disagree.
     
    Fronkjunior likes this.
  3. For a true check, Inspect the plugs after the engine is fully warmed up. You should then turn engine off without it idling.
    Have you made sure the float levels in the carbs are ok. Also no fuel is percolating into the manifolds when the engine is hot.
     
    Fronkjunior likes this.
  4. Good point, give it a good run, it won't get warm idling on the drive :)
     
    Last edited: Apr 5, 2020
    Fronkjunior likes this.
  5. Yep, this. Go for a good blast down the motorway, then check. If it's been idling with the choke(s) on, the plugs will soot up anyway, so not really telling you much.
     
    Valveandy and Fronkjunior like this.
  6. mikedjames

    mikedjames Supporter

    Mind you those plugs look like soot on black deposits.

    Get a wideband AFR meter and actually use a measurement rather than guesswork.

    Also check fuel pressure is low enough, and fuel metering needle valves are closing properly.

    Rich is usually cooler than lean on a bus so if it runs OK then leave it if you havent got test gear.
     
  7. Zed

    Zed Gradually getting grumpier

    It's all stock.
    The engine runs and drives well.
    The plugs look like they should.
    It's sat on choke then barely got warm on the drive. It's not possible to warm up the engine without a load on it.

    @Fronkjunior there's a bit of soot on some threads, particularly the top one, and the crush washers don't look very crushed so were they tightened up enough?
     
    snotty likes this.
  8. Thanks Zedders, the top one in the photo was a little lose. The other 3 were tight. Now remedied with new plugs.
     
    snotty and Zed like this.

Share This Page