ADJUSTING DRIVE BELT TENSION

A belt adjusted for proper tension can be deflected slightly at a point midway between the pulleys. An over-tight belt will cause excessive bearing wear and an under-tight belt allows slipping, causing excessive belt wear.

IMPORTANT: Never allow oil to get on the belt which could cause slipping.

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NATIONAL 68 SR & DL TRIPLEX

WING CUTTING UNIT DRIVE BELT TENSION

Adjust tension by loosening set screw (B) in the wing mower pull arm, sliding the Cutting Unit rearward and retightening set screw.

MAIN DRIVE BELT TENSION (Main Countershaft to Rear Drive)

Belt tension is increased by loosening the four bolts holding the Upper Countershaft Housing (A) and sliding the housing forward in the slotted frame holes.

NOTE - It will be necessary to remove belt guards to reach the adjustment bolts. Also, if this belt is adjusted, it will be necessary to readjust the engine belt. Replace all belt guards before using the mower.

ENGINE DRIVE BELT TENSION (Engine to Main Countershaft) (No photo)

Belt tension is increased by loosening the four engine mounting bolts and sliding the engine forward in the slotted frame holes. Test for the proper tension as detailed in the section "Wing Cutting Unit Drive Belt Tension". When tension is correct, tighten all the bolts securely.

FRONT

OF

MACHINE

REAR CUTTING UNIT DRIVE BELT TENSION

Spacers (A) are provided on the rear mower Pull Rod (B) to adjust the belt tension. Remove Pin (C) from the end of the pull rod and slip out the pull rod from the Pivot Tube

(D). Move as many spacers as necessary to the location indicated and reassemble.

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National Mower 68 DL, 68 SR Adjusting Drive Belt Tension, Main Drive Belt Tension Main Countershaft to Rear Drive

68 SR, 68 DL specifications

The National Mower 68 DL and 68 SR are two outstanding models in the world of lawn care, engineered for efficiency and ease of use. Both mowers offer a range of features tailored to meet the needs of both residential and commercial users, making them popular choices among landscapers and homeowners alike.

The National Mower 68 DL is designed with durability and performance in mind. It features a robust steel deck that enhances longevity while providing a clean and even cut. Equipped with a powerful engine, the 68 DL delivers high torque and swift acceleration, enabling users to tackle even the toughest grass and rough terrain effortlessly. The mower's advanced cutting system ensures that grass is cut finely and evenly, reducing the need for additional clean-up.

On the other hand, the National Mower 68 SR offers a self-propelled option, allowing users to move with ease across various landscapes. This model incorporates hydrostatic transmission technology, which provides smooth, variable speed control. This feature is particularly beneficial for those who demand precision in their mowing tasks, as it allow for adjustments on the fly, catering to changing terrain conditions.

Both models come with adjustable cutting height options, offering users the flexibility to choose their desired grass length. The easy-to-use lever enables quick and simple adjustments without needing tools, making the mowing process more efficient. Additionally, both the 68 DL and 68 SR are designed with ergonomics in mind, featuring comfortable handles and intuitive controls that minimize operator fatigue.

Safety is another critical consideration in the design of the National Mower 68 series. Both models come equipped with protective shields and safety switches to prevent accidental starts, ensuring that users can operate the machines with confidence.

For convenience, the mowers also feature large, easy-roll wheels that enhance maneuverability. The inclusion of a bagging system offers an option for collection of grass clippings, contributing to a cleaner lawn appearance post-mowing.

In summary, the National Mower 68 DL and 68 SR combine advanced engineering with user-friendly features that prioritize performance and safety. They are exceptional choices for anyone looking to maintain a pristine lawn with minimal effort, making yard work a more enjoyable task. Whether for home use or professional landscaping, these mowers stand out in their class, delivering reliable performance time after time.