Proper 2stroke sparkplug colour....

[Tomos770]

I miss this type of debate on this forum.....actually haven't seen one since I am here.

In "old" days when 2stroke engines were piston ported (and with mineral oils) ....coffe brown sparkplug was a norm....

Nowadays with X-torq, 2-Mix engines (and with super-duper synthetic oils) reading a sparkplug colour become a little tricky business (at least for me personally)

I screw in sparkplug the way that its electrode doesnt obstruct the flow inside the cylinder.....thats why it looks lean on one side and rich on the other....

I find that funny.....so looking forward for some comments!

So here it is a sparkplug from my stock Husqvarna 450 mk2.....last run was with XP+ syntetic Husqvarna oil @40:1 ish... (before that it was Shell advance ultra 2T @32:1)...

 

[heimannm]

History lesson for the younger fellows.

 

[lohan808]

Putting that one on the bench wall. Aces Mark!

 

[Tomos770]

Thanks....but thats "old tech" sparkplug colour chart.....

I understand it.....but look up my sparkplug from X-torq chainsaw!

It is rich on one side....and lean on the other!

Are my chainsaw setings correct?

 

[heimannm]

Your setting are 1/2 correct...you need to figure out which 1/2.........

 

[Brushwacker]

History lesson for the younger fellows.

17 to 29 look a little confusing to me.
My biggest concern is seeing grey , the color of aluminum. Then I would want to look at the piston for signs of heat damage. Anyway taking the muffler off gives a better read of how it has mostly been running, hot or cold, rich or lean. To much carbon isn't necessarily the mix ratio of fuel . I'd say more often the fuel to air which would simultaneously be feeding the cylinder extra oil which most often is caused by a air filter not breathing properly or it could be carb adjustments , or a choke not staying fully open.

 

[Vintage Engine Repairs]

 

[Tomos770]

17 to 29 look a little confusing to me.
My biggest concern is seeing grey , the color of aluminum...

Not necessarily, I had such a case with Motul 800....It left a gray deposit!
And one user here had a similar expirience with BellRay 2T oil....

 

[Vintage Engine Repairs]

Yeah that’s not a lean plug. That’s just the result of that specific synthetic oil and no lead in the fuel .

Both brown and grey depending on the oil is a good tune for them. Paper white isn’t.

 

[bwalker]

History lesson for the younger fellows.

That's for 4 cycle engines.

 

[bwalker]

View attachment 1029032

This is decent.
With that said sparkplug reading is a very coarse view of tuning.
In a saw the load changes with different size wood. That's why we jet a bit rich and hope for the best. To really get an accurate idea of state of tune a plug chop needs to be done and even then it's only accurate for the size wood you used for the chop. Staring at the end of a well used plug while satisfying doesn't really tell you a whole lot.
Another reason why Mtronic and Autotune are a good thing.

 

[ballisticdoughnut]

Generally speaking you wanna see a cardboard brown color. If the saw is behaving as it should I wouldn’t worry. That plug looks pretty normal.

 

[JoeMay]

Then there is the color of the smoke ring deep at the base of the insulator, which can only be evaluated by sawing thru the plug longitudinally. I used that evaluation successfully in my yesteryears of running a modified Yamaha RD 350.

 

[bwalker]

Then there is the color of the smoke ring deep at the base of the insulator, which can only be evaluated by sawing thru the plug longitudinally. I used that evaluation successfully in my yesteryears of running a modified Yamaha RD 350.

They make plug readers that let you view them, but the easiest way is to use a bi metal tooth hole saw to cut into the metal part of the plug. You don't have to go very deep to liberate the ceramic from the steel. Attached is two plugs from a plug chop I did on my street legal Yamaha Banshee big bore stroker.

 

[bwalker]

They make plug readers that let you view them, but the easiest way is to use a bi metal tooth hole saw to cut into the metal part of the plug. You don't have to go very deep to liberate the ceramic from the steel. Attached is two plugs from a plug chop I did on my street legal Yamaha Banshee big bore stroker.View attachment 1029328

And here are a different set of plugs from the same engine with the same jetting ran for 20 gallons of gas.

 

[bwalker]

And here are a different set of plugs from the same engine with the same jetting ran for 20 gallons of gas.
View attachment 1029329

This engine was run on Avgas and Klotz Super Techniplate castor blend or Maxima Castor 927 at 20:1. Mostly the former because Maxima didn't mix well with avgas.

 

[North by Northwest]

That's for 4 cycle engines.

Stihl Ultra 4-Mix Spark plug reference chart for beginners ! Especially the reference to valve guide wear lol.

 

[North by Northwest]

Putting that one on the bench wall. Aces Mark!

Perfect for your 68 Buick

 

[North by Northwest]

And here are a different set of plugs from the same engine with the same jetting ran for 20 gallons of gas.
View attachment 1029329

Centre & ground electrode shows proper tune colouration , little to no deposits evident with my old eyes !

 

[North by Northwest]

This engine was run on Avgas and Klotz Super Techniplate castor blend or Maxima Castor 927 at 20:1. Mostly the former because Maxima didn't mix well with avgas.

A little ash or castor oil varnish residue on the base of the ground electrode on the exhaust side of the plug , however marginal , plug chop after running it like you stole it is the only practical plug evaluation practice . As you indicated density & size of wood along with state of chain sharpness ultimately determines the accuracy of an visual inspection , to many variables . The chop is the most effective method ! P.S. Your state of tune looks very reasonable !