Testing block temp with Infrared thermometer?

[Okie]

Using a instant read infrared thermometer to monitor block temp of a chainsaw or 2 air cooled cycle engine.
Anyone have any idea what should be the normal running and operating temperature of a chainsaw block temperature? (the jug piston area)
AND
what temps would indicate that it's headed for a meltdown or operating too high of a temp?

 

[Okie]

I took 3 chainsaw saws to the wood pile and tested block temps at the piston jugs with a 3M infrared thermometer.

Idling after warmed up average 200 degrees at the jug fins.

In a full bar hard load cut 2 saws averaged 340-380 degrees with engine running loaded down. (the mufflers would get too around 450) Saws were Homelite EZ with 14 inch bar and a Homelite Super 2 with a 12 inch bar.


The Stihl 028AV saw in question owners manual indicated the initial setting on the jet as 1 1/4 out and to not go in any more than 1 turn in on the H. I checked the H jet before starting the test and the temp would rise very rapidly on the jug and was still going fast at 380 when I removed the saw from the cut and let it start cooling. I then adjusted the H jet out another 1/2 turn or 1 3/4 total expecting the saw to really gurgle and 4 cycle but only slight gurgle when throttled and would load up good in the cut and when loaded again full bar cut the temp stabilized around 340-360 max.
Test seemed to indicate saw was running really lean at manufacturers suggested initial setting going by the heat building fast and the infrared temp indicating it was headed towards another meltdown even thou the rpms were not being exceeded.
I do not have a chainsaw tachometer and don't know if a tach would have indicated a NO LOAD RPM as out of range.

This test might be similar too the biologist that was testing how far a grasshopper could jump as he removed his hind legs one at a time. His final note was: the grasshopper when both hind legs are removed he apparently becomes hard hearing and will not follow commands!

What brand and make of tachometer is good for chainsaws and not made in China? (without spending a arm and a leg)