Diagnosing your plugs
Look at the Hook on each plug and note the colour
The camera doesn't show it here - but my example here is a chocolate brown colour, which is a good sign
If its
White / Ash coloured - Its Burning lean - ie Not enough fuel, too much air
If its Just black / powder like / Dry - Its carbon, probably from short runs and not getting fully warm or you have a problem with fuel mixtures (usually carb engines)
If its Brown - Thats a good sign, A Chocolate like brown indicates a good running engine
If its Caked in black sludge / wet - Thats Oil been burnt, Not a good sign im afraid, you will need to consider further diagnostics
oil been burnt is - Worn Piston rings or bores - Worn valve guides or seals - Turbo seals blowing oil in
If the points are damaged or broken then there is lots of questions to be asked
I found this Handy little illustration off the good old web
it helps diagnose what you need to see - or not seing
The rights of the Attached link - remain with the original owner
http://www.ntractorclub.com/howtos/pdfs/Spark-Plug-Diagnostic-Chart.pdf
If you have different plugs - its advised to replace and have the same plug style and type, but if it works - the motto dont fix what aint broke comes to mind
All 4 of mine were a nice brown colour - so i checked the gap
Even if you are replacing the spark plugs - you still need to check the gap, they say they come pre-set
but dont hold your breathe, it can come a little out still
- Next page: Checking the Gap Setting
- Previous page: Getting Started
