Just how hot do lawn mowers get?!

[tiger862]

Why do you say that?

I never let it idle for very long cause it cools by fan and fins. If you cut in heat of day then high rpms cool not only engine, but differential as well. I will let it run in the shade at high rpm sometimes for 10 minutes while it cools down. At idle it can overheat especially if worked first.

 

[Sam_Julier]

My 20+ year old Honda GX-160 mulching mower runs about 165 degrees max on the hottest days in the thickest grass.

I run conventional 15W40 and power wash the cooling fins once a year. I change the oil too often.

 

[The_Eric]

I never let it idle for very long cause it cools by fan and fins. If you cut in heat of day then high rpms cool not only engine, but differential as well. I will let it run in the shade at high rpm sometimes for 10 minutes while it cools down. At idle it can overheat especially if worked first.

I feel that it is a bit of a misnomer that idling a fan cooled engine is bad for it. I get what you're saying but also keep in mind that at low speed (no load) the engine isn't producing anywhere near full power and therefor doesn't have the cooling requirements. Also with a reduction in engine speed, you have less mechanical friction, which of course requires less cooling. I've taken oil temp readings both immediately after shutting down from high speed, high load and also after a short reduced speed cool down, and they are lower after the cool down.

I generally put my rider/zero turn back to the garage at mid throttle (obviously without the deck engaged) which takes less than a minute, then down to idle for 15 to 30 seconds, then shut it down to cool off before putting it away that way I don't have to worry about hot bearings or engine parts starting grass clippings on fire.

 

[RazorsEdge]

I feel that it is a bit of a misnomer that idling a fan cooled engine is bad for it. I get what you're saying but also keep in mind that at low speed (no load) the engine isn't producing anywhere near full power and therefor doesn't have the cooling requirements. Also with a reduction in engine speed, you have less mechanical friction, which of course requires less cooling. I've taken oil temp readings both immediately after shutting down from high speed, high load and also after a short reduced speed cool down, and they are lower after the cool down.

I generally put my rider/zero turn back to the garage at mid throttle (obviously without the deck engaged) which takes less than a minute, then down to idle for 15 to 30 seconds, then shut it down to cool off before putting it away that way I don't have to worry about hot bearings or engine parts starting grass clippings on fire.

Yeah I usually idle for 3 minutes,cut grass. I take the battery blower,clean off grass debris,then drive the mower into the garage. Shut the gas off until tractor engine stops,then I park.

 

[repairman54]

I always let it idle for a minute before shutting down. Both my BS motors, 14hp and 17hp will backfire on a quick shutdown more often than not. I always hear my neighbor doing the throttled up shut down backfire on his JD. Idle is no load and airflow is still there cooling. I idle to warm up cold motors also, maybe that's why my '90's motors do not burn oil.