How to Change a Honda HT3813 PTO Clutch

ht3813Are the blades of your Honda HT3813 not spinning anymore, even though the deck and belt are in good shape? It may be time to replace the PTO clutch. This repair is more complex than most maintenance tasks, but it’s still within the means of the home mechanic.

Where is the Clutch?

Unlike most small lawn tractors, the HT3813 uses a horizontal shaft engine. The blades are driven by a belt that travels from the pulley on the deck, bending at a 90 degree angle to reach the drive pulley mounted at the front of the shaft. The front of the PTO clutch is mounted on the drive pulley and the friction plate is mounted directly behind the pulley on the engine shaft. The radiator fan and radiator are mounted directly in front of the pulley and must be removed for access to the clutch.

Tools Needed

  • A ratchet wrench with 10, 11 and 12 mm sockets. A set of deep well sockets or a ratchet extension are necessary to reach some bolts.
  • A pair of pliers, preferably hose clamp pliers.
  • An automotive jack.
  • A container to hold the engine coolant.

Since the radiator needs to be drained and removed, now would be a good time to replace the coolant.

Reaching the Clutch

Since this repair involves working around the engine and cooling system, the engine should be allowed to cool completely before you begin disassembly. Disconnect the negative battery terminal to prevent an accidental start or short.

  1. Remove the engine shroud: disconnect the headlights, then remove the two bolts that attach the shroud to the frame at the pivot point.
  2. Drain the radiator: remove the radiator cap, then unscrew the drain plug, located on the front left of the radiator.
  3. Remove the radiator: disconnect the coolant hoses from the top of the radiator, then take out the two bolts on the back side near the middle of the unit. The left side bolt will have a grounding wire running to it that should be pushed aside. Lift the radiator straight up to separate it from the tractor, then disconnect the temperature sensor at the lower right side of the radiator. Set the radiator aside.
  4. Remove the radiator fan by unscrewing the three small bolts surrounding the center crank bolt.
  5. Move the drive belt out of the way by unbolting the belt guard on the right side of the belt, then slipping the belt off of the pulley. The belt can be left on the other pulleys.
  6. Remove the center crank bolt, then slide off the fan mount and key followed by the pulley. This should uncover a second key which can be removed. The brake friction plate should now be exposed, while the clutch will be attached to the pulley.

Replacing the Clutch

If the brake friction plate needs to be replaced, loosen the bolts on the plate, then unbolt the motor mounts from the frame. Lift the engine up using a jack until the arms of the plate are above the frame. Pull the old plate off the shaft and slide on the new one. Once it’s bolted down, lower the engine and reinstall the motor mount bolts.

On the pulley, remove the three bolt holding on the backing plate. This should expose the clutch and clutch plate. When reassembling the clutch, make sure the slots line up to make space for the key.

Reassembling the Tractor

Reassemble the mower in the reverse order you took it apart. After placing the belt over the pulley and bolting on the belt guard, check the tension and adjust it using the tension knob below the front of the tractor. Remember to put the grounding wire back on the left radiator bolt, refill the radiator and reconnect the negative battery terminal.

Buying New Parts for Your HT3813

Whether you need a new clutch, belt or key, you can order it from We’re a certified Honda small engine dealer, shipping parts for everything Honda from lawn tractors to water pumps across the U.S. and Canada. Ordering is easy with our advanced part lookup system which has built-in parts descriptions and factory diagrams to help verify your order.

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