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Throttle cable, govener, and kill switch


Kent

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First, I want to say I have the B&S service manual, the original B112 operator manual, a revised B-series service manual, and a revised 3112 operator manual, and I have read them all cover to cover, and I cannot figure this out. So, I have kind of a duh question, and kind of a complicated question. First the duh. I am assembling a B112 that had no engine to begin with. I now have an engine that came from a 3112, and appears to be complete. No manual I own describes where the throttle cable attaches to the engine. I thought it was to the speed control rod, in the hole that is drilled about 1/3 of the way up. But if that is true, that leads me to the complicated question. I think I should consider the speed control rod just as a travel limiter for the throttle cable. The upper nut is supposed to set the desired operating speed of the engine (2900 rpm?), while the lower nut is supposed to set the maximum speed (3600 or 3800 rpm). If the throttle cable is attached directly to this rod, how can this rod regulate the speed between 2900 and 3600 rpm? It seems to me like maybe the throttle cable needs to be attached to this rod via a spring. If that's so, then I'm missing some parts I think. And if the two nuts limit the travel between operating speed and overspeed, how does the engine speed ever get to idle? Then there's the two holes next to the control rod in the same braket, the top hole bigger than the lower hole. Some of my manuals show a cable routed through these holes during the operating speed and idle speed settings of the govener. But I think this is just a speed calibration fixture, not the tractor mounted throttle control. And finally, there is the upper pivot lever that the gov. springs and speed control rod attach to. There is one or two unused holes on the opposite side of the pivot. Maybe the throttle cable or something else should be attached there? All the manual illustrations are unclear about that side of the arm. So I guess I'm hoping someone can describe how the throttle cable should attach to the B112 engine, and describe better than the manuals do, the calibration technique of the governed speed limits and what each of the external speed control parts do. I could be wrong, but I don't think a lot of people really understand this part of engine maintenance and repair. Oh yea, while we're here, how should the ignition kill be connected? All the manuals show the spark plug mounted kill bar. The engine has a wire that exits the cover that originates from the armature. On my engine, this wire terminates to a spade connector, which is attached to another wire and a broken piece of insulated board, the kind you usually see live wires mounted to to insulate them from the engine ground. I'm assuming this board is supposed to be mounted to the engine somewhere, and then proceeds on to the dash ignition switch. I guess I'm just looking for confirmation of that. If that's true, I'll just shrink wrap a wire connection there and not worry about mounting it to the engine block. But if there's supposed to be a local kill switch on the engine, I must be missing it. Whew, Greg
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Greg THE throttle cable does mount in the hole about 1/3 down the control rod.The throttle cable houseing is then mounted to the top the intakemanifold with L-bracket in the 1/4 20 hole in the manifold. THE kill wire bracket mounts under the top bolt of the points cover.The then goes to the ing.switch Greg hope this will help good luck R.C.
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Greg, some clarification. The connections are as R.C. says. The control rod controls the govener max speed, but the gov. controls the throttle butterfly on the carb. If you have a heavy load the gov. could have the throttle wide open to try to maintain the rpm set point even at a low rpm setting. The wire for the ignition is connected as R.C. says and when you turn off the ignition switch you are actually grounding that connection, similar to grounding the spark plug to kill the engine. With the switch ON this wire is "open" not connected to anything. Hope this helps. MS
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