Saw spark plug getting insanely hot.

[DudeManDan]

Hello people. Having an issue with a few of my Husky 372 xpg's. Same problem on two saws now, one of which is brand new. I run the saw for a few hours and eventually the saw will stall out and I notice an abnormal smokyness coming from the top of the power head. When I inspect the spark plug I notice it's insanely hot. The spring seems to be stuck ot the spark plug and the first time this happened I ripped the boot in half leaving the spring still attached to the plug. Recently had the same issue with a saw that was new last year. It ran just fine for a while(about 2 weeks of hard working) until I was led to believe a richer oil mixture would be good for the saw. The only consistent thing about these two saws is the oil/fuel mixture. Which was rich. My question really is, if I mixed my fuel too lean or too rich would it cause this problem? If not do you have any idea as to why the spark plug and the power head would be so hot?

 

[PV Hiker]

I looked up where Comox Valley is and looked at your past temperatures were. Your in Canada. In our area we have winter grade fuel with additives to burn hotter for cleaner emission. If we burn this fuel in a two stroke on a hot day it will cause the piston to expand from the increased temperature.

Apparently this does look like your problem as you have not been over 50 degrees Fahrenheit.

Did you change fuel type or product when you changed oil ratios?

 

[DudeManDan]

I looked up where Comox Valley is and looked at your past temperatures were. Your in Canada. In our area we have winter grade fuel with additives to burn hotter for cleaner emission. If we burn this fuel in a two stroke on a hot day it will cause the piston to expand from the increased temperature.

Apparently this does look like your problem as you have not been over 50 degrees Fahrenheit.

Did you change fuel type or product when you changed oil ratios?

So I actually am working in fox creek Alberta. About -10 to 3 degrees on average. I use 93 octane and using husky or Stihl oil. Usually mix it at 50:1. This last batch possibly lost more oil in the mix then I thought when I had a minor spill while mixing. I was going rich anyway so I thought nothing of it.

 

[Bob Hedgecutter]

Photos of the plug electrodes might shed some light on the situation.
Plugs burning hot tend to eat the electrodes.
Might be tuning or air leaks (running real lean), ignition timing up the woop..... or easier to check- incorrect spark plug heat range.

 

[Conquistador3]

Are your saws standard or was timing advanced? Are you using aftermarket ignition modules? What spark plug grade are you running?

Finally zero cost fix: try buying fuel from another service station.

 

[rd35]

I'd start by checking all the cooling air passages to make sure plenty of cooling air is able to cross through the cylinder fins. Compressed air is my best friend when it comes to saw maintenance!!!!

 

[rd35]

Also, are all of your engine covers in place and in good shape? Damaged covers will also impede cooling as they can no longer direct the air from the flywheel fan to where it needs to go!

 

[Brent Nowell]

Are you using the winter kit?
If so stop, this could be your problem. It is only designed to be used if your sucking up snow from the ground into your side cover intake. It may be restricting it too much.

Also check to see if the louvers on the side cover are icing up restricting flow. I’m certain you have a cooling problem here, which is not related to fuel.

 

[DudeManDan]

It is a brand new husky 372 xp g. Completely stock. I did have a winter kit on it when it started to overheat which was the the last 5 trees felled and bucked in a day where I cut 14 down in total. I am working in the snow and never had an issue in the past using a winter kit. I also inspected the piston today and noticed what must be scoring. Not really my area of expertise but I'm learning my way around the saw. I had the same exact issue with my previous saw that I was using the same fuel in. Overheating in the top end and spark plug getting extremely hot. Smoking from the top not muffler

 

[sunfish]

If a piston looks scored, do not run the saw until checked out. Sounds like you messed up the last can of mix.

 

[nwmo_aggie]

I was led to believe a richer oil mixture would be good for the saw

Explain this statement a bit, and what is was that you did. Did you change the gas to oil mix ratio? If you did, did you adjust the carb?

 

[SteveSr]

Hello people. Having an issue with a few of my Husky 372 xpg's. Same problem on two saws now, one of which is brand new. I run the saw for a few hours and eventually the saw will stall out and I notice an abnormal smokyness coming from the top of the power head. When I inspect the spark plug I notice it's insanely hot. The spring seems to be stuck ot the spark plug and the first time this happened I ripped the boot in half leaving the spring still attached to the plug. Recently had the same issue with a saw that was new last year. It ran just fine for a while(about 2 weeks of hard working) until I was led to believe a richer oil mixture would be good for the saw. The only consistent thing about these two saws is the oil/fuel mixture. Which was rich. My question really is, if I mixed my fuel too lean or too rich would it cause this problem? If not do you have any idea as to why the spark plug and the power head would be so hot?

Running more oil WILL cause a leaner (less gas) running condition. Sounds like you are too lean and close to seizure.

 

[Brent Nowell]

Your sure that the intake louvers were not iced up?
To me it just sounds like no air flow. Either that or a vacuum leak

 

[DudeManDan]

I was led to believe a richer oil mixture would be good for the saw

Explain this statement a bit, and what is was that you did. Did you change the gas to oil mix ratio? If you did, did you adjust the carb?

I messed up my fuel mixture. Lean on oil. It's the only only explication. Just sloppy when mixing.

 

[DudeManDan]

Your sure that the intake louvers were not iced up?
To me it just sounds like no air flow. Either that or a vacuum leak

It was however a brand new saw. Off chance water got in the carb through the fly wheel due to a lot of snow, or maybe didn't warm it up well enough when breaking it in? Seems unlikely. I'm attempting a warranty fix so all these things may be helpful to know and are worth looking into.

 

[mountainlake]

You NEED to open up the high needle a little, it's not the oil they run hot when adjusted to lean. Steve

 

[MacAttack]

If there was excessive oil in the fuel it would have been smoking excessively from the exhaust, did you notice that?

I don't intend to start an argument, but for the sake of diagnosing your problem, in my personal first-hand experience with various 2-strokes, an overly oil-rich fuel mixture has resulted in a smokey, lazy, plug-fouling performance, which seems like a rich tuning condition that fouls up your plug and gets excess oil in your exhaust but does not score a piston or damage the engine. I'm not about to go run a 10:1 mix in one of my saws to further validate but this has been my experience in dirtbikes, snowmobiles, etc. My bet would be more likely you didn't use enough oil or your jetting is lean for your ambient temperature.

 

[sunfish]

I agree, it's not too much oil that would cause this. I think too little oil in the mix caused it to both saws.

 

[mountainlake]

They are adjusted too lean, he said he was running a rich oil mixture which only make them run a little leaner as the thicker mix cant get though the carb as easy. I'll bet these saws are screaming. Steve

 

[sunfish]

They are adjusted too lean, he said he was running a rich oil mixture which only make them run a little leaner as the thicker mix cant get though the carb as easy. I'll bet these saws are screaming. Steve

I've heard that can happen, but have never experienced it. Have switch for 50:1 to 32:1 and saws didn't run too lean. But who know?