Troubleshooting - Cub Cadet 990 Series Operator's Manual

6
Trouble
Shooting
For repairs beyond
the minor adjust-
ments listed here,
contact an authorized
service dealer.
Problem
1. Blade control disengaged.
Engine fails to start
2. Spark plug wire disconnected.
3. Fuel tank empty or stale fuel.
4. Engine not primed.
5. Faulty spark plug.
6. Blocked fuel line.
7. Engine flooded.
8. Burnt fuse. (Electric Start Only)
Engine runs erratic 1. Spark plug wire loose.
2. Blocked fuel line or stale fuel.
3. Vent in gas cap plugged.
4. Water or dirt in fuel system.
5. Dirty air cleaner.
6. Carburetor out of adjustment.
1. Engine oil level low.
Engine overheats
2. Air flow restricted.
3. Carburetor not adjusted properly.
Occasional skips 1. Spark plug gap too close.
(hesitates) at
2. Carburetor idle mixture adjustment
high speed
Idles poorly 1. Spark plug fouled, faulty or gap
2. Carburetor improperly adjusted.
3. Dirty air cleaner.
Excessive
1. Cutting blade loose or unbalanced.
Vibration
2. Bent cutting blade.
Mower will not
1. Wet grass.
mulch grass
2. Excessively high grass.
3. Dull blade.
Uneven cut
1. Dull blade.
Mower will not
1. Belt not installed properly
self propel
2. Debris clogging drive operation.
3. Damaged or worn belt.
Cause
improperly set.
too wide.
16
Remedy
1. Engage blade control.
2. Connect wire to spark plug.
3. Fill tank with clean, fresh gasoline.
4. Prime engine as instructed in
"Operating Your Lawn Mower".
5. Clean, adjust gap, or replace.
6. Clean fuel line.
7. Wait a few minutes to restart, but
do not prime.
8. Replace fuse (see Maintenance
section)
1. Connect and tighten spark
plug wire.
2. Clean fuel line; fill tank with clean,
fresh gasoline.
3. Clear vent.
4. Drain fuel tank. Refill with
fresh fuel.
5. Refer to engine manual.
6. Refer to engine manual.
1. Fill crankcase with proper oil.
2. Remove blower housing
and clean.
3. Refer to engine manual.
1. Adjust gap to .030".
2. Refer to engine manual.
1. Reset gap to .030" or replace
spark plug.
2. Refer to engine manual.
3. Refer to engine manual.
1. Tighten blade and adapter.
Balance blade.
2. See an authorized service dealer.
1. Do not mow when grass is wet; wait
until later to cut.
2. Mow once at a high cutting height,
then mow again at desired height or
make a narrower cutting path.
3. Sharpen or replace blade.
1. Sharpen or replace blade.
1. Check belt for proper pulley instal-
lation and movement.
2. Stop engine, disconnect spark plug
wire, and clean out debris.
3. Inspect and replace belt.