John deere 4115 compact utility tractor service repair manual

Page 49

ENGINE - 21 HP DIESEL DIAGNOSTICS Symptom: Engine Runs Rough - Engine surges DURING IDLING No - Repair or replace fuel injector pump and fuel injectors. Go to step (3) if problem continues. (3) Proper spray pattern from injectors? Yes - Go to step (4). No - Clean or replace fuel injector nozzles. Go to step (4) if problem continues. (4) Piston rings not broken or seized? Yes - Go to step (5). No - Replace rings, Check pistons and cylinders. Go to step (5) if problem continues. (5) Crankshaft pin or bearing not worn or seized? Yes - Go to step (1). No - Grind crankshaft and replace bearings. Go to step (1) if problem continues.

Symptom: Engine Runs Rough - Engine surges UNDER LOAD

Symptom: Engine Runs Rough - Excessive Engine Vibration (1) Even volume of fuel injected? Yes - Go to step (2). No - Repair or replace fuel injector pump and fuel injectors. Go to step (2) if problem continues. (2) Proper spray pattern from injectors? Yes - Go to step (3). No - Clean or replace fuel injector nozzles. Go to step (3) if problem continues. (3) Piston rings not broken or seized? Yes - Go to step (4). No - Replace rings, Check pistons and cylinders. Go to step (4) if problem continues. (4) Crankshaft pin or bearing not worn or seized? Yes - Go to step (5). No - Grind crankshaft and replace bearings. Go to step (5) if problem continues. (5) Connecting rod bolts torqued properly?

(1) No water in fuel? Yes - Go to step (2).

Yes - Go to step (1).

No - Drain and replace fuel. Go to step (2) if problem continues.

No - Replace damaged components. Torque to correct specification. Go to step (1) if problem continues.

(2) Even volume of fuel injected? Yes - Go to step (3). No - Repair or replace fuel injector pump and fuel injectors. Go to step (3) if problem continues. (3) Proper spray pattern from injectors? Yes - Go to step (4).

Symptom: Engine Runs Rough - Poor return to low speed (1) Go to steps procedures for “Engine Runs Rough�. Fuel Consumption

No - Clean or replace fuel injector nozzles. Go to step (4) if problem continues. (4) Piston rings not broken or seized? Yes - Go to step (5). No - Replace rings, Check pistons and cylinders. Go to step (5) if problem continues. (5) Crankshaft pin or bearing not worn or seized? Yes - Go to step (1). No - Grind crankshaft and replace bearings. Go to step (1) if problem continues.

Symptom: Excessive Fuel Consumption (1) Engine not running too cool? Yes - Go to step (2). No - Check thermostat, replace if faulty. Go to step (2) if problem continues. (2) Correct volume of fuel being injected? Yes - Go to step (3). No - Replace faulty fuel injector pump or fuel injectors. Go to step (3) if problem continues. (3) Correct pattern from fuel injectors? Yes - Go to step (4).

Engine - 21 hp Diesel Diagnostics - 45


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