My Ford 9N Adventures – Part2: The Governor

Tractors have the original cruise controls. You set the (engine) speed and go. When the tractor needs more power, to get up a hill or to cut heavier brush, the governor automatically “gives more gas.” Technically, for those who care, the governor acts on the throttle, which is what the “gas pedal” in (older) cars opens and closes. Not to be too pedantic, but fuel injected cars (which are most of them nowadays) don’t exactly have a throttle because they don’t have a carburetor. But I digress.

So the governor is like cruise control, you set it and it takes care of maintaining the power (or speed.) The governor on old Ford tractors works with a set of steel balls that spin inside a housing between two plates. One of the plate is concave, the other one flat. When the engine speed increases the ball move away from the center of the plates (by centrifugal force) which forces the concave plate to be pushed away from the other (sliding on the shaft.) This in turn causes the governor to adjust the throttle to slow the engine back down to the desired speed. There’s a little more to it, but you get the idea.Search the web for “Ford 9N governor diagram) and you’ll find lots of images that may help you understand.

I told you that to tell you this: These plates and balls are on a shaft that spins around because it is attached to a gear that is driven off of the timing gear. The running engine turns the timing gear, the timing gear turns the governor gear and the governor gear turns the guts inside the governor. Well, to get right to the point, the gear on the governor that came with my 1941 9N turned freely on the shaft, instead of causing the shaft to turn.

The old governor with its free-spinning gear

After debating how best I might fix the gear to the shaft so they would turn as one unit good old Tony (you remember Tony, Corinne’s nephew) found a spare governor in his collection of parts from his years of restoring (and using) old 9Ns. He was kind enough to give it to me and now it’s on the tractor and doing its job.

There were two issues I had to sort out before I installed the governor, which is what the post is really about! The first issue is a very common one with these units. They have a spring which gets stretched out over time and needs to be tightened up. There should be no slack in the linkage that the spring is part of, but the spring also should not be under tension. Long story short, I successfully shortend the spring (too much) and then lengthened it until it was just right.

Issue two was the lack of a gasket which goes between the governor and the engine. Time to make a gasket. Having recently moved and most of my shop is still hiding in boxes in the barn, I had to buy some gasket paper and gasket compound. The method I’ve always used to get the right shape to a gasket is to use the part that it’s going to go on and a hammer to lightly tap the paper on the part, making a nice clear outline of the outside and inside.

Tapping the paper on the part
The outline thus created.

All that was left was to cut out the gasket, apply the gasket compound to both sides and bolt the governor back onto the engine… well, not exactly. I still had to reconnect the rods that connect the speed lever next to the steering wheel and the one that connects the governor to the carburetor. These rods have spring loaded sockets that fit on the balls on the levers they connect to. Being old and full of years of farm gunk, the sockets are hard to open up fully to get them onto their balls. The one that connects the governor to the carburetor is especially challenging as it runs behind the carb and is thus hard to hold while you’re trying to open the socket. My ingenious (if I do say so myself) solution was to tie the carburetor lever that the one end of the rod was already attached to allowing the use of both hands to attach the other end to the governor. That’s what this final picture shows.

Well, that was enough fun for today. Who knows what adventure I’ll have tomorrow.