7 replies to this topic

[pusb]

Just changed my spark plugs, I know that you're suppose to be able to tell a lot about the condition of the engine from the colour of the plugs. Looking on google it says that they should be a light tan colour, and black soot is a sign of a rich mixture. Mine is somewhere in the middle, a grey colour, and I cant seem to find anything that says what grey indicates. Could it be that its running just slightly rich?

 

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[Spider]

Mixture looks pretty OK, however it does look like you're also burning a fair bit of Oil.

[pusb]

Mixture looks pretty OK, however it does look like you're also burning a fair bit of Oil.

 

The ends of the plugs are dry, all the oil was on the threads. Would that be consistent with burning oil?

[A-Cell]

It's the heavy deposit of black tarry soot inside the plug that indicates it is burning oil. The tip of the plug and electrodes show the mixture to be ok, chocolate colour there as far as I can see in the picture

[pusb]

It's the heavy deposit of black tarry soot inside the plug that indicates it is burning oil. The tip of the plug and electrodes show the mixture to be ok, chocolate colour there as far as I can see in the picture

 

Bad enough to worry about do you think? Or just general aging?

 

The engine runs fine, doesn't smoke, and gives good oil pressure.

[dyshipfakta]

Ok wouldn't worry too much then. Using abit of oil is ok just keep an eye in it and perhaps clean the plugs up every once in a while. Until you start using silly amounts of oil or you have oil pressure and running problems I would leave it.

[Alpenflitzer]

1) correct spark plug?   2 correct gap

If Plug and electrodes are 

 

COMBUSTION IS OK

Light to dark grey is oK. Brown deposits become rarer due to less additives in the fuel

 

ENGINE IS OVERHEATING

 Electrode glassy, insulation body very light discorolored

Probably wrong heat value of the spark plug or wrong octane. Can also happen if the engines overheats.Engine runs too hot

Wrong Spark plug (too hot), lean mixture

 

SOOTY

Black and soot

Wrong plugs (too cold). Air/fuel mixture too richt. Ignition not correct.

Edited by Alpenflitzer, 27 September 2015 - 04:10 PM.

[Ethel]

The best time to assess plug colour is after a long run, so it's had chance to burn off excess soot from starting & warming up.