Exmark makes a wide variety of commercial grade mowing equipment; all have a 12-volt electric PTO clutch system to operate the mower blades. When the PTO switch is engaged the clutch brake also engages causing the blades to turn. After hours of wear on the clutch, it will start to slip causing a poor quality of cut. When this happens an adjustment must be made, this procedure will take 20 minutes to complete.
Things You'll Need
Feeler Gauge
5/8-Inch Wrench
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Step 1
Park the lawn mower on a level surface and turn the ignition key to the "off" position. Set the parking brake and and disengage the PTO switch on the dash.
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Step 2
Locate the PTO clutch bolted to the crankshaft of the engine, behind the pulley on the clutch are three adjustment screws. Place the 0.31 mm feeler gauge in between the two brake plates; just below one of the adjustment screws, the feeler gauge should be able to move while the two plates rub against each side of the feeler gauge. Check under the other two adjustment screws. If at any of the three points, have a air gap between the feeler gauge and the brake plate an adjustment needs to be made.
Step 3
Keep the feeler gauge between the brake plates; tighten the adjustment screw above the feeler gauge until the feeler gauge starts to bind. Repeat this step under the other two adjustment screws. Start the mower, engage, and disengage the PTO several times. Recheck the adjustment to ensure it was done correctly.