Engine Overspeed Governor - TM-5-4320-258-340022

TM 5-4320-258-34

(7) Inspect the balls (8)-for scoring, nicks,

(1) Remove the screw (1) to release the

and other damage; replace damaged balls.

governor drive shaft assembly (items 2 through 15) from

(8) Inspect the drive gear (9) for damaged

the governor housing (33).

gear teeth, worn or scored internal diameter, and

(2) Slide the retaining ring washer (3)

damaged drive notches; replace a damaged drive gear.

toward the upper race (7) on the drive shaft to expose

(9) Inspect the fork and bumper spring (21)

the retaining ring (2). Remove the retaining ring and

for wear and distortion. Replace damaged parts.

slide the washer (3), ball stop washer (4), fork base (5),

(10) Inspect the governing shaft (24) and

thrust bearing (6), and upper race (7) from the drive

lever (23) for wear and distortion; replace damaged

shaft assembly. This will release the four balls (8).

parts. (11) Inspect the governor housing (33) for cracks,

(3) -Support the drive gear (9) in a press

damaged bores, distorted mounting flange, and other

and press the drive shaft (14) from the gear. Remove

damage; replace a damaged body.

the governor base (10) with the assembled bearing (11),

d. Reassembly. Reassemble the governor as

lower race spacer (12), and the lower race (13) from the

shaft.

shown in figure 3-4. Note the following:

(4) Press the ball bearing (11) from the

(1) Lubricate all operating parts with clean

governor base (10).

engine oil during reassembly.

(5) Do not attempt to press the driver (15)

(2) If the bushing (29) was removed from

from the drive shaft (14) unless either of the parts is

the bushing seat in the governor housing, place the

damaged.

thrust washer (30) in the seat and press the bushing

(6) Drive out the groove pin (19) that

squarely into the seat, taking care not to damage the

secures the fork (20) to the governing shaft (24). Pull

bushing end. Press it in until it is firmly seated against

the assembled governing lever (23) and shaft (24) from

the thrust washer.

the governor housing (33) to release the fork. Remove

(3) When pressing the drive gear (9) onto

the fork.

the end of the drive shaft (14), lubricate the end of the

(7) Pierce the expansion plug (25) and pry

shaft with engine oil and press the gear squarely onto

it from the governor housing (33) along with the gasket

the shaft. Take care to support the opposite end of the

(26).

shaft in a manner which will prevent peening or burring

(8) Insert a soft drift through the needle

the shaft end.

bearing (28) on the expansion plug side of the housing,

(4) After installing the retaining ring (2), pull

and drive out the oil seal (27) and the needle bearing

the retaining ring washer (3) over the retaining ring to

(28) from the housing. Insert the drift from the opposite

lock it in place.

side and drive out the remaining needle bearing.

(5) After reassembly, rotate the governor

(9) If the bushing (29) is damaged, thread it

shaft. It must turn freely without binding, scraping, or

with a tap of suitable size and turn a bolt into the

catching.

e. Installation. Install and adjust the governor

threaded bore. Pull the assembled bolt and bushing

from the housing (33).

on the engine (TM 5-4320-258-12).

c. Cleaning and Inspection.

3-5.

Engine Overspeed Governor

a. Testing and Adjustment. The engine over-

(1) Clean the bearings as directed in

paragraph 2-7.

speed governor must shut off the engine when engine

(2)'Clean all remaining parts by washing in

speed reaches or exceeds 2700 rpm. Test and adjust

cleaning solvent (FED. Spec. P-D-680); dry thoroughly.

as follows:

(3) Inspect the bearings for rough, catching,

(1) Start the. engine and allow it to warm

or binding operation. Check the balls or rollers for

to operating temperature, then shut it off.

scoring and check the races for damage. Replace

(2) Disconnect the linkage from the engine

damaged bearings.

speed governor (TM 5-4320-258-12) so that the engine

(4). Inspect the upper race (7) and the

speed can be controlled by manually manipulating the

lower race (13) for scoring, cracks, and distortion.

carburetor throttle lever. Caution: Do not operate the

Check the internal diameter of the bores for an out-of-

engine at speeds greater than 2750 rpm. Engine over-

round condition. Replace damaged races.

speed can result in severe engine damage.

(5) Inspect the driver for scoring, cracks,

(3) Restart the engine and have an

wear in the ball pockets, and other damage; replace a

assistant watch the tachometer. Slowly increase engine

damaged driver.

speed with no load until the engine stops as the result of

(6) Inspect the drive shaft for misalinement

the operation of the overspeed governor or until the

and for wear at the bushing end. Replace a damaged

tachometer indicates 2750 rpm.

shaft.

3-8