ENGINE - 21 HP DIESEL DIAGNOSTICS Symptom: Exhaust temperature too high
Symptom: Engine Runs Rough - Misfiring
Yes - Go to step (1).
Yes - Go to step (1).
No - Replace rings. Replace pistons if damaged. Bole cylinder if damaged. Go to step (1) if problem continues.
No - Replace damaged components. Torque to correct specification. Go to step (1) if problem continues.
Symptom: Engine Runs Rough - Misfiring (1) Intake or exhaust valve clearance correct?
Symptom: Engine Runs Rough - Uneven combustion sound (1) Correct type of fuel being used?
Yes - Go to step (2). No - Adjust valve clearance. Go to step (2) if problem continues. (2) Timing between injection pump, intake and exhaust valves proper?
Yes - Go to step (2). No - Drain and replace fuel. Go to step (2) if problem continues. (2) No water in fuel?
Yes - Go to step (3).
Yes - Go to step (3).
No - Adjust valve clearance. Check valve timing. Go to step (3) if problem continues.
No - Drain and replace fuel. Go to step (3) if problem continues.
(3) Backlash of timing gear not excessive?
(3) Even volume of fuel being injected?
Yes - Go to step (4).
Yes - Go to step (4).
No - Repair gears as needed. Go to step (4) if problem continues.
No - Repair or replace fuel injector pump and fuel injectors. Go to step (4) if problem continues.
(4) Combustion chambers clean of foreign matter?
(4) Proper spray pattern from injectors?
Yes - Go to step (5).
Yes - Go to step (5).
No - Clean combustion chambers. Go to step (5) if problem continues.
No - Clean or replace fuel injector nozzles. Go to step (5) if problem continues.
(5) Intake or exhaust valves not leaking compression? Yes - Go to step (6). No - Grind valves and seats. Go to step (6) if problem continues. (6) Intake or exhaust valves not seized? Yes - Go to step (7). No - Replace valves and check valve guide. Go to step (7) if problem continues. (7) Piston rings not broken or seized? Yes - Go to step (8). No - Replace rings, Check pistons and cylinders. Go to step (8) if problem continues. (8) Crankshaft pin or bearing not worn or seized? Yes - Go to step (9). No - Grind crankshaft and replace bearings. Go to step (9) if problem continues.
(5) Air filter elements not clogged? Yes - Go to step (6). No - Clean or replace air filter elements. Go to step (6) if problem continues. (6) Exhaust pipe not clogged? Yes - Go to step (1). No - Clean exhaust pipe. Go to step (1) if problem continues.
Symptom: Engine Runs Rough - Engine surges DURING IDLING (1) No water in fuel? Yes - Go to step (2). No - Drain and replace fuel. Go to step (2) if problem continues. (2) Even volume of fuel injected? Yes - Go to step (3).
(9) Connecting rod bolts torqued properly? Engine - 21 hp Diesel Diagnostics - 44