Briggs 2-3.5 Pulsejet Vaccujet governor throttle

#1
If you have questions, please send me a personal message, as I won't be checking on the thread...

I realize the pics suck, and will update them...


The majority of governor systems consist of a ( governor spring ) to regulate engine speed, and a (governor) to FIND the engines running speed...

The majority of, "but not all", Briggs & Stratton 2-3.5, and some newer (faker) 4 horse power engines, use a Wind Vane to find the engines running speed.

The wind being blown through the engines cooling system, via the cooling fins on the flywheel, passes by the (wind vane) which is mounted to the ignition coil. The faster your engine runs,the faster and harder the air is blown through the blower housing, and against the Wind Vane.

The Wind Vane and (throttle plate) on the carburetor are linked directly together via a steel (linkage rod). The position of the Wind Vane directly controls the amount of throttle being given to the engine....

Below where the linkage rod is attached to the arm on the wind vane, are a series of holes, running vertically up the arm.. The (governor spring) will attach to ONE of theses holes in the series.. The higher up on the arm you attach the spring, the more leverage and mechanical advantage you gain over the governor resulting in a higher top speed the engine will reach...

The OTHER END of your (governor spring) attaches to a small rotating arm, bolted to the side of the carburetor. When the top of this arm is pulled, you pull tension on the spring, pulling the wind vane back against the wind, causing the throttle to be pushed open, resulting in the engine speeding up. :scooter:

When the engine reaches it's pre-determined (governed speed of 3,600 rpms) the wind vane is blown back by the rushing air, and the engine is no longer allowed to accelerate. No matter how far you pull the spring, the wind vane has final say in how fast the engine is allowed to run, via the amount of tension the governor spring is allowed to have by placing it in the proper hole on the arm on the wind vane....

Holy Cow.. :laugh:

first pic, the governor system in it's entirety, at a dead idle position, no throttle attached..





Next, the throttle cable....

In a perfect world, there will be a second (return spring), behind the rotating arm which is pulling your governor spring.. This second (return spring) works on a twisting action and is very stiff.. When you release pressure on the throttle grip and cable, this second spring "returns" the entire system back to zero...

In a realistic world, you do not have this second spring.. In this case, you will need some sort of ( return spring) pulling the end of the rotating arm back to it's zero position. I like to use a longer top shroud bolt, with a nut and lock washer between the bolt head and blower housing. Run the bolt in to a safe depth, then run the nut and lock washer down tight.. This will result in an open space in the bolt, that makes for a nice perch for your (return spring) to hook onto... wrapping a spring around your shroud will result in paint loss from the spring rubbing, so keep that in mind on a nice looking motor..

The finally, your cable... This will attach to the top hole in your rotating arm. The cable sheath is clamped into place, at the rear of the carb, via a small clamp... If you clamp is gone, a small washer will also work...

 

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