Mounting a throttle position sensor to the ZS CD-150 is done without altering the carburetor so it can still function as a carburetor or now as a throttle body.
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Installation |
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For clarity only, the photo shows the idle speed adjustment screw and the water choke removed. You don't need to remove the water choke at this time. The original nut holding throttle linkage onto the end end of the throttle shaft can be removed with a 7/16" or 12MM wrench. Turn counter clockwise to remove it. Remove the nut and the star washer behind it. |
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Shown here is the new TPS driver installed (early version of driver in photo). DO NOT over tighten it as it will strip the threads on the throttle shaft and that can only be repaired by replacing the shaft! Place a wave washer from the kit onto the shaft and thread on the driver in place of the original nut. Notice that it is slotted and that the slot is off center to mesh with the tabs inside the sensor. At idle, the driver should be positioned with the black colored lobe as shown in the next photo. Down inside the driver is a set screw that is tightened to lock the driver in place and allow adjustment.
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This is what the bracket will look like once installed. Notice the angle of the driver's slot at idle. The top bracket tab goes under the bolt holding the spring retainer on the intake manifold.
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The bracket mounts to a carb mounting stud underneath the carb. Removing the nut will require a 1/2" open end wrench. With this nut and the top mounting bolt removed, the bracket can be installed. It is tricky but it can be done. Start with the driver thru the hole in the bracket then lay the bracket over the stud and finally working it in place at the top on the manifold. Put the nut and bolt on finger tight.
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Position the bracket so that the driver is centered in the hole then tighten the mounting bolts. If the alignment is still off you may need to adjust the bracket with a pair of pliers.
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Install the sensor using the two screws supplied. You will likely need to wiggle the sensor or move the throttle shaft to engage the sensor's tabs. Be sure the tabs are engaged properly before tightening the mounting screws. Using your hand, be sure that the throttle moves freely over it's range without binding or sticking. Reinstall the water choke. That's it. |
