Usage:
Introduction
Many starting motors are the same, but their nose housings are in a different position. If the part numb that was ordered is different from the original part number, the position of the nose housing may need to be changed.
Do not perform any procedure outlined in this publication, or order any parts until you read and understand the information contained within.
Reference: Parts Book; Service Manual
Removal
Remove the electric starting motor from the engine. See the Service Manual for the correct procedure.
Modification Procedure
1. Measure angle (A) between solenoid (B) (or any special location on the starter) and hole (C) on the old and new starters. If the angles are not the same, remove nose housing (1) from the new starter and move it to the same angle (A) as the old starter.
2. For starters with a solenoid, tighten 5/16-18 bolts (2) to a torque of 18 to 23 N·m (13 to 17 lb ft) and M6 bolts to a torque of 12 to 14 N·m (8.9 to 10.4 lb ft). Use a metal stamp to put the new part number on the plate.
3. For starters without a solenoid (may have a relay), tighten bolts (3) to a torque of 10 to 14 N·m (7.5 to 10 lb ft). Use a metal stamp to put the new part number on the plate.
Ground Stud Relocation (If Necessary)
NOTE: When replacing a 9X1490 Motor Group with a 9X1489 Motor Group, it may be necessary to change the location of the ground stud. If after rotating the nose housing, the ground stud interferes with the engine block or there is not sufficient space to install the ground cable, relocate the ground stud using the following procedure.
1. Remove ground stud (4).
2. Remove pole shoe screw (5) with a T-40 Torx Driver.
3. Install pole shoe screw (5) into the position previously occupied by the ground stud (4). Torque to 180 to 600 in lb.
4. Install ground stud (4) into the position previously occupied by the pole shoe screw (5). Torque to 180 to 600 in lb.
Analyzing Starting Motor Failure
Analyze starter failure prior to installing a replacement starter.
Starter damage often results from attempting to crank with low battery (cranking) voltage on the electric starter. Engine ring gear damage may result in this situation. There are three main reasons for starter failure
- 1. Wearout during normal starter life (2000 to 5000 hours).
Wearout refers to normal or expected starter life. The starter needs replacement because:
- * the commutator brushes are too short.* the nose housing bearings are worn (sloppy). * or the solenoid contacts are no longer a good switch to connect the battery to the starter.
The result is a starter that no longer cranks or might crank sluggishly. In this situation, the starter and starter solenoid show no real visual signs of failure. The drive gear is NOT broken or blue from heat, the armature shaft is NOT blue, there are no "hot" spots sometimes easily visible on a painted housing.
- 2.(a) Starter stays engaged with ring gear during start-up.
Several things may cause starters to stay in mesh with the engine ring gear during start-up. Indications that this has occurred include:
- * Blue, badly worn, or broken starter drive gear; or worn bearing.* Excessive wear in the armature shaft bearing of the nose housing.* Armature shaft that is locked up and cannot be rotated.* "Hot" spots in the paint on the brush end of the starter.* Solenoid coils are open, shorted, or smell burnt.
If the above symptoms are observed, the starter is not usually at fault. Check for one of the following problems:
- * Stuck or sticking dash mounted start switch (most probable).* Stuck or sticking solenoid contacts (check battery).* Stuck or sticking starter relay (if applicable).* Failure of the wiring harness, battery positive-to-start circuit, anywhere between the start switch and the starter solenoid. This includes connectors. Look for contamination shorting contacts inside a connector shell.* Loose and/or incorrectly positioned wiring on the solenoid. This may cause the solenoid to engage the starter.
If any of the symptoms above are noted, but the exact cause cannot be identified, replace the start switch.
- 2.(b) Starter attempts to reengage the ring gear after start-up.
A starter that is replaced because the drive attempted to reengage with a running engine ring gear shows one or more drive teeth "milled" or chewed up on the leading edge.
This fault is usually caused by operator error or an intermittent faulty "start" signal to the starter from a start switch, start relay, or harness fault.
- 3. Damage from low voltage on the starter motor.
The results of low voltage on the starting motor while cranking can be:
- * Sluggish cranking.* No cranking or maybe only a "click".* Starter can be heard to "chatter" or pulse the drive in and out of the ring gear at a rapid rate.* Solenoid gets hot and may even weld the contacts closed so that the starter tries to crank continuously, or may run (operate) without cranking the engine. See the illustrations. The solenoid contacts show a burnt or "smoked" spot (and sometimes, melted) while the rest of the contact area shows previous starts were normal.* One or more (but not all) starter drive teeth show case crushing of the hardened tooth surface.* Badly chipped, or broken engine ring gear teeth.* Bent armature shaft at drive end caused by engine "rock-back."* Twisted armature drive splines that cause the drive to "stick" on the armature shaft.
Solenoid contacts.
Damage to solenoid contacts because of low batteries.
Contact disc.
Damage to contact disc because of high current as from high engine cranking, parasitic loads or low batteries.
Contact disc.
Damaged contact disc from high cranking current because of low batteries.
Contact disc.
Normal wear pattern on contact disc.
Possible causes of the above results or faults are:
- * Low or no alternator output.* Loose fan belt(s) causing low or no alternator output.* Battery problems such as a shortened cell.* Poor/loose connections between the batteries and starting motor. This means anywhere in the positive or negative (disconnect switch) leads.
NOTE: Correct any of the above listed problems prior to installing a replacement starter.
Install the electric starting motor on the engine. See the Service Manual.