Small engines...why 3600 RPM?

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Sharpshooter
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Do you have any idea why basically everything with a small engine is set to run at 3600 rpm? I was curious what a Cub Cadet runs at and in looking that up I find that that is a pretty standard RPM which seems weird that so many different applications use the exact same RPM. Seems that most lawn mowers, snow blowers, generators etc are all set to the same engine RPM. Any ideas?

The closest thing that I could find had to do with small engines on generators and 3600 RPM being 60 revolutions per second which helps with the 60 hertz that is used for electricity in the states, but what the heck does that have anything to do with lawn mowers and snow blowers and pressure washers and all that? I know that there are obviously some that do not run at this rpm, but it seems like a majority of them do. So what's magic about 3,600 rpm?
 

Snattlerake

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Obviously, it is the optimum RPM that lasts the longest time, that doesn't get overheated, with torque and horsepower at a nominal level.

I have no freakin idea.
 

Rod Snell

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Small engines are governed to around 3600rpm which is the world standard for small PTO's Every country has a maximum blade tip speed limit for mowers and this is reducing all the time. Micro engines (chain saws & the like) have no standard.
 

Shadowrider

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I think @Snattlerake is pretty close.

It's because they have to be relatively lightweight which means engine cases which support crankshaft loads have to be thin and cylinder walls have to be somewhat thin for air cooling. If they ran 5 to 6000 RPM they wouldn't live long.

Two strokes are completely different animals, they do run high RPM but don't really live very long in comparative run hours.
 

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