Reading a spark plug
 

This a 2 stroke plug and it's supposed to have oil on it. But is this too much?

BTW, the tip broke off when coming home, fortunately 1/2 block from the house. Replacement is on the way. I had a premonition something would happen soon when Manny Moe and Jack didn't carry them. :rolleyes:

Edit: spelling

http://forums.pelicanparts.com/uploa...1456278904.jpg
http://forums.pelicanparts.com/uploa...1456278924.jpg

You have a 2 stroke 911? Do tell.

JR

Looks like it's running a little rich or too much oil in the gas. Is the oil to gas mixture correct? My GT380 plugs burn cleaner. Could also need a hotter range plug.

The spec manual is in metric and converts to 40/1 aka 4 ounces to a gallon.

You might want to check your math. 4 ounces to a gallon is 32:1, not 40:1. Big difference, for a two stroke.

JR

Well it runs on that, the plug shows the results. It looks rich. So, I'm guessing if I haven't burned it up it's OK.

Spark plugs that have some miles on them or have been used..engine at idle..etc are near impossible to "read"..even for the experts.

A fresh plug..run at a specific throttle position and a "clean chop" ignition off and coasting to the side of the road is the proven way to "read' spark plugs.

Here is a write up by the master..Gordon Jennings, RIP. A little dated but the techniques are all good.
How you can read spark plugs and select them - by Gordon Jennings.

Running too much oil effectively leans your air/fuel mixture, so I'd say your jetting is off more than you think. It's hard to tell from the poor picture but the idle mixture might be richer than the main jet mixture and the plug reach may be wrong as well.

As Mr. cooper noted above, that plug is not a good candidate for a read, anyway. Two strokes are a little harder to read than 4 strokes.

JR

http://forums.pelicanparts.com/uploa...1456331538.jpg
funny you had the broken top connector. Mine was plane gone when I pulled mine out!

Reading spark plugs requires a procedure called a "Plug Cut". This involves operating the engine at a fixed throttle setting long enough for temps to stabilize, cutting the ignition, then coasting to a stop. After that, one removes a plug and carefully inspects the color of plug's porcelain insulator.

It does take some experience to "read" the insulator and interpret the results. :) :)

So what engine is a 2 stroke?

Champion's Bobby Strahlmann could tell you what the rider had for breakfast.....

Usually a smaller engine that has compression,spark fire, exhaust in the same stroke of the piston. As opposed to a Porsche 4 stroke. Oil is either injected into the fuel for lubrication or premixed in the tank. There is not crank case oil as the oil in the fuel is also the crank case lubricant.