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« on: December 11, 2016, 09:40:31 PM »
It took me a while to figure this out, the drawing in my Lister parts manual only shows one bob weight, once I'd pulled it all to bits things became clearer.
Without the governor connected the fuel rack won't move - bear with me! - so if it's fully closed there's no fuel to the injector and it won't run, period.
With the rack fully open the machine will over fuel on start up and then rev until something lets go.
The governor holds the rack fully open with the bob weights against the camshaft, until there is enough centrifugal force to spin them outwards, pulling against the spring to allow the linkage to move, this movement CLOSES the rack.
Less tension, or a weaker spring, will allow movement at lower revs, thus reducing the maximum speed the governor will permit.
An increase in load, drawing more power from the generator, for example, will momentarily slow the engine, the bob weights will be drawn in towards the centre line of the camshaft, by the spring and the revs will increase until the bob weights and the spring reach a state of equilibrium and the revs remain more or less constant.
It was worth typing all this to use the word equilibrium!
Several members, the last was Ed Dee I think, use a very light spring pulling the rack to the closed position to eliminate the back lash from the 'sloppy' linkage, others have rebuilt the linkage with rose joints and some are, I believe experimenting with electronic control.
Hope that this helps, failing that, pull it to bits!
Cheers Stef