fearofweapons Posted December 2, 2019 Share Posted December 2, 2019 (edited) Hello! So my wife's SIII SWB has a 90 2.5 petrol in. We discovered the other day that the #1 plug had no nipple for the lead to attach to - no wonder it was running a little rough and less power. Not knowing the age of the plugs we decided to replace them all. The photos below are of the ones removed. To my untrained / uneducated eye these look OK. What do you think? The left hand side of the photo are different sides of the same plugs the right hand side ditto. Edited December 2, 2019 by fearofweapons Quote Link to comment Share on other sites More sharing options...
Gazzar Posted December 2, 2019 Share Posted December 2, 2019 They look a little bit sooty, don't they? Does that mean the engine is a bit rich? Quote Link to comment Share on other sites More sharing options...
simonb Posted December 2, 2019 Share Posted December 2, 2019 (edited) All a bit rich except for perhaps the far RHS one on the top image. The electrode and insulator nose should be a light sand colour with just a thin coating of deposits. What was the last MOT emission readings - even a Series 3 needs to be below 4.5% CO and 1200ppm HC. A well tuned example should be well in - mine was 0.36% and 223ppm for instance. Have you got the Zenith carb from the Series 3, or the carb from the 90? Edited December 2, 2019 by simonb Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted December 2, 2019 Share Posted December 2, 2019 LMGTFY... https://ngksparkplugs.com/en/resources/read-spark-plug https://www.championautoparts.com/Parts-Matter/automotive-repair-and-maintenance/how-to-read-spark-plugs.html https://www.hotrod.com/articles/mopp-0612-reading-spark-plugs/ http://www.crankshaftcoalition.com/wiki/Reading_spark_plugs Quote Link to comment Share on other sites More sharing options...
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