Governor precision; how good should it be in a small engine

[four winds]

BTW, manual says speed fluctuation is 30 RPM or less for a 3gm30f. Which is consistent with my experience in operation.

[a64pilot]

Four winds, that manual page is absolutely correct of course Yanmar wrote it
But what isn't well explained is that governed RPM is set, not variable. 3600 RPM in my engine, so if I push the throttle full open in neutral, then the governor will hit that equilibrium point the manual speaks at 3600 RPM and reduce fuel to keep the engine from exceeding governed RPM. Any RPM less than the point at which the flywheel weights don't open up, the governor may as well not be there. It is in effect a rev limiter

The link to the training film Stone Beach posted, explains it very well

Pressure and volume are interrelated. An injector has a spring valve in it that keeps the injector closed until X amount of pressure, then the valve opens and as long as pressure is above X, fuel flows. The pressure if graphed would look like a bell curve and the lower point of the bell would have the injector dribbling instead of spraying, so whenever pressure is lower than what will give a good spray pattern, the injector valve is closed.
Old fashioned mechanical injector of course, common rail and HEUI etc are way different.


Sent from my iPad Pro using Cruisers Sailing Forum