Plugs

[Doug01]

I haven't been on this site in a while but I was wondering..............do spark plugs go bad?

Doug

 

[ShoerFast]

Doug

In a word, Yes!

But the 2 dollar , 2 minnute test is to replace the plug.

Kevin

 

[Lakeside53]

Rarely if the saw is working well and the gas/oil is a reasonable mixture.

If your plug is oils soaked, carboned up, coated with whatever, worn electrode etc, just chuck it, then fix the problem (mixture adjustment, gas mix, whatever). They only cost $1.00 - $2.50. Use a good brand of like Bosch, NGK, NTN etc. Make sure it's the correct temperature range for the saw (see your manual).

If you run a plug long after it should have been replaced, there is a chance the ceramic around the center electrode will fracture and parts will drop into your saw. Not good.

If you are running a saw hard, replace the plug at least annually. If just occasional use, every two-three years. It could be done on hours of use basis, but who really counts that well?

 

[DeanBrown3D]

My 200's plug was covered in a light brown powdery coating. That normal? Saw worked better once I brushed it down.

 

[ShoerFast]

My 200's plug was covered in a light brown powdery coating. That normal? Saw worked better once I brushed it down.

As just for myself, I wouldn't brush off a plug.

For a couple bucks, just replace it, if the effects of "brushing it down" would dislodge some of the debris just enough to flake off the next time the plug got hot, could increase the chance of the debris getting lodged in the piston, and score a cylinder.

Kevin

 

[Justsaws]

The dealers around here get close to $5.00 for a Bosch spark plug. Thank goodness for Bailey's.

 

[Rotax Robert]

Sounds like the color is right light brown/tan. Just as long as it is not white or black.

Rotax Robert

 

[Lakeside53]

The dealers around here get close to $5.00 for a Bosch spark plug. Thank goodness for Bailey's.

For a saw? hmmm... that's only a 600% markup if you buy them a 100 at a time. Even the Stihl MSRP is than $5.00, and nobody buys plugs from Stihl!

 

[Doug01]

Black = rich......right???

 

[Lakeside53]

Right, but that's not necessarily bad...

 

[RED-85-Z51]

On a 2 stroke engine, the Oil is brought into the crankcase with the fuel/oil charge. The oil, being thicker than gas, tends to stick around in the the case, in the needle bearings on the crank, and in the rod. Some of it is puled into the combustion chamber, and lubes the upper cylinder and ring(s).

If you run an engine Rich, it has ample lubrication, and generally good throttle repsponse, but it lacks RPMS because the excess fuel takes slightly longer to burn.

If you run an engine Lean, the crancase lubrication is low, the bearings get HOT, the cylinder gets hot, the whole engine starts to overheat. The soft metals start to break down, the top of the piston gets extremely hot, and any oil that is there is instantaniously rendered useless and it burns off. The fuel, when it enters the cylinder starts to pre-ignite from the excessive temperatures. At this point, if the bottom end is still holding together, the detonation will start to beat on the piston, and actually cause the fuel to blow before the piston covers the exhaust port. This condition is known as "lean pop" and is a WARNING SIGN to back off, and richen the mixture, or face major damage, or Further damage. If the engine is allowed to continue to run, it will likely seize up, break the rod, or burn a hole in the piston.

The key is to find the sweet spot, right in the middle, that provides enough fuel to keep the engine cool and lubed, but not enough to impede on performance.

Generally, if an engine is too lean, it will "fall on its face" upon accleration, which means you give it full thorttle, the exhaust note faulters then the engine slows and eventually stops. All that is happening is the piston goes up, the plug fires, but there isnt enough fuel to cause an explosion.

White plug= Lean engine
Tan/dark tan = The sweet spot
Black/oily= Rich or excessive oil mixture.

In contrast, on a 4 stoke engine, there is a whole host of other issues.

Rich mixture can cause the cylinder t obe wiped clean of the oil film, causing clylinder, piston, and ring wear.
Lean mixture can lead to excessive heat, and overheating, possibly detonation, but the engine would be running so poorly and making so little power, it would be obvious there is a problem.

4 strokes are more accepting of a less than optimum fuel/air mixture than 2 strokes.

 

[Just Mow]

Red, don't forget to credit the author.

 

[04ultra]

Red, don't forget to credit the author.

Yup...

 

[Just Mow]

Ultra, how did you get the picture under your log in name ?

 

[RED-85-Z51]

Red, don't forget to credit the author.

Sorry Dude, beleive it or not, I typed all that.

 

[RaisedByWolves]

Ultra, how did you get the picture under your log in name ?

Same way you got yours there.



What happened to the puppy dog?

 

[04ultra]

One thing everybody over looked ..They will spoil if not refrigerated..:hmm3grin2orange: :hmm3grin2orange:

 

[RED-85-Z51]

Has anyone tried this new style of spark plug..sold in Home Depot. Looks different, has a forked ground diode.

I put on in my old snapper, and it ran with more throttle response, and idled smoother.

at 7 bucks a pop..Im hesistant to buy one for a saw, they seem to be sort of universal for 2 strokes.

I dont remember what they are called or the brand, but if youve shopped for plugs in a box store, youve seen em.

 

[DanManofStihl]

forked plud

I bought one of the E3 plugs from advanced auto parts. I could not tell any difference between the auto lite plug and that one. I don't think it was worth the extra money personally.

 

[Kneejerk Bombas]

I haven't been on this site in a while but I was wondering..............do spark plugs go bad?

Doug

Spark plugs do not go bad. So to answer your question in a word, no.