Mid America Motorworks 602-781 User manual

Mamotorworks
@CorvettePassion
MidAmericaMotorworks
CorvettePassion
INSTRUCTION SHEET
Part Number
2900 North Third Street, Effingham, IL 62401
800.500.1500 • Worldwide: 217.540.4200 • FAX: [phone]
www.mamotorworks.com • [e-mail]
©Mid America Motorworks, Inc. All rights reserved.
Application:
Tools Needed
Dash & Center Console
STEP 1.
Removing the odometer set knob is the most difficult step in this process. With
a pocket screwdriver, press firmly on plastic tang as shown in Diagram A. Wiggle
knob free from stem.
STEP 2.
Remove three small Phillips screws from top of Speedo/Tach lens and one from
each side (Diagram B).
STEP 3.
Remove lens.
STEP 4.
Remove six Allen head screws that hold the face plate over the speedo/tach and
remove (Diagram C).
STEP 5.
Remove three screws that hold Tach housing. Remove tach by pulling unit from
housing.
STEP 6.
With tach laying face down on clean surface, remove three nuts (Diagram D)
that hold printed board to tach and remove defective board.
STEP 7.
Install new board. Replace three nuts. Install tach unit in tach housing.
STEP 8.
Start engine and check tach.
STEP 9.
If properly adjusted, tach needle should rest at normal idle (around 1000 rpm).
If tach needle rests at higher than normal idle, needle is out of adjustment.
Shut engine off to adjust needle.
STEP 10.
602-781
Part Includes
1 - Tach Board Replacement
3 - Flat Washers
Tachometer Circuit Board Rebuild Kit
Corvette 1978-1982
Bottom side of trip knob
Tang
DIAGRAM A
Lens Screw Location
DIAGRAM B

INSTRUCTION SHEET
Toll Free: 800.500.1500 • Worldwide: 217.540.4200 • www.mamotorworks.com • [e-mail]
000-000
Description (cont.)
Page 2
STEP 10.
Turn key to “run” position (without starting engine). Needle will “cycle” and
stop. Leave ignition key in “run” position until Step 13.
STEP 11.
Carefully remove tach needle by wiggling it straight up. DO NOT ROTATE THE
NEEDLE.
STEP 12.
Set needle to “0” and gently push back in place without rotating needle.
STEP 13.
Start engine and check with a tach gauge. Tach should read correctly. If not
repeat steps 10, 11, and 12. Remember, DO NOT ROTATE THE NEEDLE DURING
REMOVAL OR INSTALLATION.
STEP 14.
Replace lens and odometer reset knob.
Face Plate Screw Location
DIAGRAM C
Tach Board Nut Location
DIAGRAM D