Saw spark plug getting insanely hot.

[sunfish]

H

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

He also said he lost oil when mixing last can? I'm betting a screw up here & he didn't get enough oil in the mix.

 

[SteveSr]

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.

Another thought... Saws also get leaner (assuming that they are not computer controlled) as the ambient temperature decreases. Cold air is more dense. More air to the same amount of gas = leaner mixture. Were these saws ever tuned for your particular running environment?

 

[mountainlake]

Your right, if tuned good for hot weather they need to add more fuel when it gets cold. Steve

 

[CR888]

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 tend to agree, this saw should not be run until its tuned and this problem is addressed. Hopefully no damage has occured to P/C. Run em hard & lean and they will get HOT.

 

[Okie]

I did not read all of this thread but if not already suggested to you:

You need to get yourself a infrared thermometer gun and take the temp of the block of the saw. You can get one now days at a reasonable price and get one that has good reviews.
If the saw is running lean the block will overheat and sometimes very rapidly especially if in a full bar cut. (other things can cause the block to overheat but the thermometer will let you know if the block is actually overheating and headed for self destruct)

If the chain is sharp you will find that you can monitor the temp by yourself with a log laying on the ground using the gun type Infrared thermometer. If you see 375F and headed for 400F fast the saws piston is going to expand fast and ruin the cylinder walls and the saw is headed for self destruct.



IR temp of chainsaws block temp using a IR thermometer.

Nominal OK temp 350F if reached slow in in a full bar cut.

If the temp is rising fast and gets to 375 headed for 400 take it out of the cut and let the engine cool down to 350 or less before killing the saw. Do not kill it when hot or it may continue overheating or won’t cool off fast.

I do the temperature test on my saws and have found that it is a really good test to confirm that the carb is tuned properly to prevent overheating during hard use of the saw. But again it may not just be the carb. Test the temperature.

 

[Bob Hedgecutter]

Willing to bet, these saws were making that nightmarish metallic "tink- tink"of rapid cooling when shut off quick as the smoke was noticed.
Also do not like the odds of a great outcome to any warranty repair claim.

 

[PV Hiker]

Yes, if your saw is hot, let it idle to cool down. Air flow over the head from flywheel and fuel coming in. Helps to prevent vapor-lock also.

If the OP was cutting in the snow it would be interesting to know if the flywheel cover was blocked off with snow to prevent air flow. As some have mentioned iced up.

Make sure your mix is right, take the time or start over. Gas and oil is cheap enough to dump in your vehicle tank and start over with a known mix. A lot cheaper than a new top end.

There is a plus and minus values of working safety margin. A adjusted value zone is wide enough to accommodate for some changes in fuel delivery, fuel-oil mix, altitude, temperature. If more of these values are combined at the extremes is where you have problems.

EDIT to add... Even if the flywheel cover is open, snow and /or sap sawdust can pack the flywheel fins and limit airflow.