Troubleshooting - Cub Cadet SC 621 Operator's Manual

SECTION 10: TROUBLE SHOOTING GUIDE
Trouble
Engine fails to start
Engine runs erratic
Engine overheats
Occasional skip (hesitates)
at high speed
Idles poorly
Excessive vibration
Mower will not mulch grass 1. Wet grass.
Uneven cut
Refer to separate engine manual packed with your mower for more engine related information.
NOTE: For repairs beyond the minor adjustments listed above, contact your nearest Cub Cadet dealer.
Possible Cause(s)
1. Blade control handle
disengaged.
2. Spark plug wire disconnected.
3. Engine not primed.
4. Fuel tank empty, or stale fuel.
5. Blocked fuel line.
6. Faulty spark plug.
7. Engine flooded.
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.
2. Air flow restricted.
3. Carburetor not adjusted
properly.
1. Spark plug gap too close.
1. Spark plug fouled, faulty or
gap too wide.
2. Carburetor out of adjustment.
3. Dirty air cleaner.
1. Cutting blade loose or
unbalanced.
2. Bent cutting blade.
2. Excessively high grass.
3. Dull blade.
1. Wheels not positioned
correctly.
2. Dull blade.
Corrective Action
1. Engage blade control handle.
2. Connect wire to spark plug.
3. Depress primer bulb slowly three
times.
4. Fill tank with clean, fresh gasoline.
5. Clean fuel line.
6. Clean, adjust gap or replace.
7. Wait for the engine to dry out.
1. Tighten spark plug wire.
2. Clean fuel line; fill tank with fresh
gasoline.
3. Clear vent.
4. Drain fuel tank. Refill with fresh fuel.
5. Clean air cleaner.
6. Adjust carburetor. Follow engine
manual.
1. Fill crankcase with proper oil.
2. Remove blower housing and clean.
3. Adjust carburetor.
1. Adjust gap to .030".
1. Reset gap to .030" or replace spark
plug.
2. Adjust carburetor. Follow engine
manual.
3. Clean air cleaner.
1. Tighten blade and adapter. Balance
blade.
2. Replace blade.
1. Wait until later to cut.
2. Mow once at a high cutting height,
then mow again at desired height or
make a narrower cutting swath (1/2
width).
3. Sharpen or replace blade.
1. Place all four wheels in same height
position.
2. Sharpen or replace blade.
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