for the past couple of months, I had convinced myself that my 362 was running too hot. I have been doing a lot of cutting lately and when I killed my saw, it felt too hot. So, I fattened up the carb a bit which seemed to help a little. Then, I read on hear somewhere that some let their saw idle for 30 seconds or so to allow cool down. Soooooooooo I tried it and BINGO!! Makes sense that it would cool a saw down and it does. What I had been doing was after I cut several big rounds, I would kill the saw to get a drink of water and when I picked the saw back up to crank it, it seemed too hot and it was. Makes a very big difference. This cool down idle is probably common knowledge but I had never tried it. I thought i a had a pending saw problem but I don't. My old Mac PM 700 was 32-1 and drank gas so I guess I never noticed as much heat( richer in oil less heat I guess?) Anyway, I read the tip and it works.
Sounds like you've got it figured out... Do you have an IR gun? You could track post-idle-cool down shut off temps a few times to put yer mind at further ease?
Very good point. I always try and let my diesel powered truck idle for a few minutes after hauling a load of wood home. Lots of weight to pull so I know things get warm.
Well this is interesting to read, I definitely did not know this but more than likely use this info after I've been running any saw constantly.
That also applies to a push mower, riding mower, and trimmer. Now if you let them sit there and idle all day they might over heat because the fins on the flywheel help cool the engine. 2-3 minutes is probably long enough. I even let the Kubota BX idle some after mowing and it is a liquid cooled diesel.
So this allows the excess gas to burn off from the use or? Would you tell me what's happening during idle that allows a better cool down?
The idle speed itself generates much less combustion heat than higher speeds do, especially under load. With the engine still running there is cooling air or water still flowing...or in the case of a 4 stroke engine air/water/oil all still flowing and cooling. As previously mentioned an it doesn't take long, an idle period of a few minutes is normally plenty...in the case of a chainsaw, I'd say 30 seconds would do it for most saws
The reason behind letting diesels with turbos cool down, is the turbo spins 1000 rpms per 100 engine rpms. when they are hot and still spooled up and you shut it off the oil is not pumping to the turbo and the little that is left will cook off and wear the bearings prematurely.
I generally do not idle them down. Maybe 10 seconds.... I do not cut a 36 inch round with a full chain overworking the saw, and have had no issues.
One more bit of clarity here...for turbos, the oil is the bearing, when running the turbo shaft floats on a thin layer of oil being injected all around the shaft. So cut off the engine (oil pressure) when she's still hot and spooled up...yeah, doesn't end well. It grinds into the bushing that the oil comes through which fouls up the clearances...very NOT gooder! That's why if I ever bought any high dollar turbo diesel, I'd install pre-lube system. It pressurizes the oil system before you crank the engine over with an electric pump, then keeps it pressurized for a bit after shut down too. You'd have almost zero engine bearing wear...
