Alamo SR14, SR20 manual Tractor Drawbar Length, Operation, Based on Mower Operating Speed

OPERATION

2.3 Tractor Horsepower

The horsepower required to operate the mower depends on several operating factors including the vegetation to be cut, terrain condition, operator experience, condition of the mower and tractor, and others. For most mowing conditions, the SR14 and SR20 mower requires a tractor with a minimum of 75 HP. Operating the mower with a tractor that does not have adequate power may damage the tractor engine. Exceeding 100 HP for a 540 RPM drive and 140 HP for a 1000 RPM drive may cause mower damage by overpowering the unit in heavy cutting conditions.

2.4 Drawbar

The tractor drawbar must be positioned at a certain length based on the operating speed of the mower for proper driveline operation. If the mower is a 540 RPM unit, position the drawbar length from shaft end to hitch hole at 14”. For 1000 RPM mowers, set the drawbar length at 16” for 21 spline 1-3/8” mowers and at 20” for 1-3/4” 20 spline mowers.

Ensure that the drawbar is rated to carry the tongue weight of the mower.

Tractor Drawbar Length

(Based on Mower Operating Speed)

	14" (540 RPM 1-3/8”-6)
TONGUE	16" (1000 RPM 1-3/8”-21)
	20” (1000 RPM 1-3/4”-20)
		DRAWBAR

Pintle Hook Hitch-Optional Equipment

Drawbar length must be modified to obtain dimension "A" (CV Driveline = 17" ± 2", Standard Driveline = 19 ± 2").

Tongue

PTO

Shaft

A

Drawbar

OPERATION

P i n t l e Clevis

Tongue Cont. Rod

P i n t l e Hook

Pintle Hook Mount

2.5 Tractor Hydraulics

The mower center section and each wing are positioned with hydraulic cylinders that are operated by the tractor hydraulic pump. The tractor must have a minimum of 2 hydraulic control valves devoted to the mower unless the tractor is fitted with a 3-spool control valve (extra equipment).

A 3-spool control valve is required if the tractor is equipped with a single valve and is recommended for those with two valves so that the center section and each wing can be controlled independent of one another. Refer to the Assembly Section of this manual for properly equipping the tractor with a 3-spool control valve. Tractors equipped with three hydraulic ports can position the center section and each wing independently with no extra equipment. If the tractor is equipped with only two hydraulic ports and a 3-spool control valve is not used, the wings cannot be operated independently and will raise and lower at different speeds.

SR14/SR20 10/03 Operation Section 4-7

© 2004 Alamo Group Inc.