WARNING: Before inspecting, cleaning or servicing the machine, shut off engine, wait for all moving parts to come to a complete stop, disconnect spark plug wire and move wire away from spark plug. Failure to follow these instructions can result in serious personal injury or property damage.

FORWARD CLUTCH

BAIL ADJUSTMENT

If the Forward Clutch Bail does not func- tion properly, first check that the forward drive belt is adjusted properly (see Check- ing and Adjusting Forward Drive Belt Ten- sion). If this fails to correct the problem, contact Troy-Bilt LLC or your authorized dealer for service advice.

CHECKING AND ADJUSTING RE- VERSE DRIVE BELT TENSION

(Models 643B & 645A only)

It is important to maintain correct tension on the reverse drive belt. A loose belt will cause the tines and wheels to slow down – or stop completely – even though the en- gine is running at full speed.

When checking belt tension, also check the belt for cracks, cuts or frayed edges and replace it as soon as possible.

•Check belt tension after the first two hours of break-in operation and after every 10 operating hours.

To Check Reverse Belt Tension:

1.Stop engine, wait for all parts to stop moving and disconnect spark plug wire.

2.Remove screw in plastic belt cover and slide belt cover (which is attached to for- ward clutch cable) out of the way.

3.Have an assistant pull the Reverse Clutch Control knob all the way out and hold it in that position. Measure the length of the cable wire between the end of the threaded cable adjuster (A, Figure 5-5) and the end of the Z-fitting (B) to which the ca- ble wire is attached.

4.The belt tension is ideal if the cable wire length measures between 1/8" to 1/4". If it is less than 1/8" (and if there is no reverse ac- tion when the tiller is running), then make the following adjustments

NOTE: If the length is more than 1/4", no ad- justment is needed—as long as the reverse action functions properly.

5.Release the Reverse Clutch Control knob.and then unthread the inner jam nut (C, Figure 5-6) one to two turns. Pull the threaded cable adjuster (A, Figure 5-6) to the left until the inner jam nut (C) touches the bracket.

6.Prevent the inner jam nut (C) from turn- ing and tighten the outer jam nut (D) against the bracket. Prevent the outer jam nut (D) from turning and tighten the inner jam nut (C) against the bracket.

7.Measure the gap by repeating Step 3. Readjust as needed by repeating Steps 5 and 6.

8.Reinstall the belt cover.

A B

Figure 5-5: Measure cable wire length to check for correct reverse belt tension.

D C A

Figure 5-6: Move threaded adjuster (A) to left to increase belt tension.

Replacement Belt Information

If the drive belt needs to be replaced, see your local authorized dealer or refer to the Parts List for ordering information. Use only a factory-authorized belt as an “over- the-counter” belt may not perform satis- factorily. The procedure requires average mechanical ability and commonly available tools.

ENGINE CLEANING

Keeping the engine clean will help to en- sure smooth operation and prevent dam- age from overheating. Refer to the Engine Owner’s Manual for engine cleaning ser- vice intervals and instructions. Be sure that the muffler is cool before servicing the engine.

AIR CLEANER SERVICE

The air cleaner filters dirt and dust out of the air before it enters the carburetor. Op- erating the engine with a dirty, clogged air filter can cause poor performance and damage to the engine. Never operate the engine without the air cleaner installed. In- spect and service the air cleaner more of- ten if operating in very dusty or dirty conditions. Refer to the engine Owner’s Manual for air cleaner service intervals and instructions.

ENGINE OIL SERVICE

Check the engine oil level before each use and after every five hours of continuous operation. Running the engine when it is low on oil will quickly ruin the engine.

It is recommended that you change the motor oil after every 10 hours of operation and even sooner when operating in ex- tremely dirty or dusty conditions. Refer to the Engine Owner’s Manual for detailed service instructions.

A. To Check the Engine Oil Level:

1.Park the tiller on a level area and shut off the engine.

2.Level the engine (use the Depth Regula- tor Lever to adjust the engine angle).

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Troy-Bilt 643B Super Bronco manual Forward Clutch Bail Adjustment, Engine Cleaning AIR Cleaner Service Engine OIL Service
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643B Super Bronco specifications

The Troy-Bilt 643B Super Bronco represents a robust and versatile addition to the world of outdoor power equipment, designed with the needs of gardeners and landscapers in mind. This rear-tine tiller is a notable choice for those looking to cultivate their gardens efficiently and effectively.

One of the standout features of the Troy-Bilt 643B is its powerful 306cc OHV engine, which provides ample torque and ensures that the tiller can tackle tough soil conditions with ease. This engine is specifically designed for superior performance and reliability, allowing users to till effectively in a variety of soil types, from sandy loam to clay.

The tiller boasts a 12-inch tilling width and a tilling depth of up to 8 inches, making it ideal for preparing garden beds and landscaping areas. The adjustable tilling depth allows gardeners to customize their cultivation process, enabling them to penetrate deeper for planting larger crops or more shallow for seedbed preparation.

Equipped with a rear-tine design, the Super Bronco brings several advantages. The rear-tine configuration provides better control and stability while working, making it easier to maneuver in tight spaces. Furthermore, the counter-rotating tines help to break up compact soil while reducing the chances of soil clumping, resulting in a finer tilled surface.

Another remarkable feature is the Troy-Bilt patented "Smart Till" technology, which allows users to select the most suitable tilling method for their specific soil conditions. This innovative technology enhances efficiency, saves time, and ensures that the tiller delivers optimal results with every pass.

For ease of use, the tiller is equipped with large, easy-grip controls and a comfortable handlebar design that reduces fatigue during extended use. Additionally, the rugged construction and all-terrain tires enable the Troy-Bilt 643B to navigate challenging landscapes without issue.

The maintenance of the Super Bronco is user-friendly, with features that facilitate easy access to essential components for tune-ups and repairs. Overall, the Troy-Bilt 643B Super Bronco combines power, technology, and practicality, making it an excellent choice for both novice and experienced gardeners seeking to enhance their outdoor projects.
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