Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Ok I read couple of different papers regarding how governor works.  Still confused.  Say an egnine support to run at 3500 RPM.

Is this true: when the engine load increases, RMP drops, governor moves arm(due to RPM change),  arm pushs the throttle opens more,  engine back to the same speed.  So no matter what load the engine has the RMP stays the same.

If that is true when does the governor spring comes in to play?  How is the engine idle speed accomplished if governor suppose to set the engine speed to 3500 RPM?

OK.  This one seems explains better. http://eu-en.myfaqcenter.com/Answer/?p_faqid=3832

There is another governor spring inside the engine to balance the governor spring outside the engine.

On most small engines.  The governor inside the engine is made up of a gear and two or three spinning weights on a shaft.  As the weights spin faster they move on a shaft and push a spool against the governor arm inside the crankcase.  That moves the governor arm/shaft outside the engine.  It's a mechanical system there are no springs involved inside the engine.
The governor spring on the outside of the engine pulls against the force of the governor arm.   That is why if you have a stretched or worn out spring the engine RPM
can sometimes hunt up and down.  When there is no load on it.  There needs to be a certain amount of tension pulling or working against the mechanical governor. To make the whole system
work correctly.   The idle speed is set with the idle adjustment screw on the carburetor. The governor sets or controls the top end of the RPM range.  The throttle control, controls and adjusts
the RPMs from idle setting up to full throttle. 
On most 2 cycles SS blowers.  The governor spring tension and setting, pulls the throttle wide open.  And it stays there.
Some engines have a vane under the shroud.  That is moved by the air coming off the flywheel.  That is the governor system for those engines it's not internal.  Some of the Toro SS blowers
have that system.

jrtrebor wrote:
My little Ariens SS has the vane-under-the-shroud type of governor. It's a Tecumseh engine, and does not have a throttle control for the user (it's always at full RPM).