Engine Will Not Crank

Forward/reverse pedals out of neutral position.

Mow/Transport lever not in transport position.

Park brake not engaged.

Backlapping valve engaged.

Loose or corroded battery connections.

Low battery output.

Sulfated or worn out battery.

Starter faulty.

Blown fuse.

Melted fusible link.

Engine Hard To Start

Gas Model: Faulty spark plug.

Loose or corroded electrical connections.

Stale fuel.

Plugged filter.

Diesel Model: Air in system.

Engine Will Not Start

Diesel Model: Fuel shut-off valve closed.

No fuel.

Wrong fuel.

Plugged fuel filter.

Stale fuel.

Gas Model: Spark plug wires loose or disconnected.

Engine Misses Under Load

Gas Model: Faulty spark plug.

Stale fuel.

Diesel Model: Air in system.

Engine Runs Rough When Hot

Fuel tank vent plugged.

Dirty fuel filter.

Gas Model: Engine or carburetor not grounded well.

Gas Model: Debris in carburetor.

Gas Model: Coolant low in radiator.

Gas Model: Dirt and debris in radiator fins.

Engine Runs Unevenly

Loose electrical connections.

Choke or throttle cable sticking.

Diesel Model: Air in system.

Engine Will Not Idle

Spark plug not gapped correctly.

Faulty spark plug.

Loose throttle cable.

Improper idle speed adjustment.

Engine Backfires

Gas Model: Faulty spark plug.

Allow engine to cool prior to shutdown.

Engine Knocks

Stale or low octane fuel.

Engine overloaded.

Low engine speed.

Engine Loses Power

Engine overheating.

Too much oil in engine.

Dirty air cleaner.

High altitude operation.

Gas Model: Faulty spark plug.

Engine Overheats

Plugged oil cooler.

Air intake grille screen plugged.

Low coolant level.

Engine oil low.

Low Oil Pressure

Engine oil level low.

Plugged oil filter.

Faulty oil pump. (See your John Deere dealer)

Engine Emits Black Smoke

Excessive fuel.

Dirty air cleaner.

Engine overloaded.

Diesel Model: Dirty or faulty fuel injectors.

Engine Emits White Smoke

Diesel Model: Low Cetane fuel.

Low engine temperature.

Head gasket leakage.

Engine Oil Contaminated

Gas Model: Faulty spark plug.

Operating machine in rainy or humid conditions.

Poor fuel quality.

Starter Does Not Work

Loose or corroded connections.

Low battery output.

Sulfated or worn out battery.

Faulty starter.

Starter Cranks Slowly

Low battery output.

Sulfated or worn out battery.

Engine oil too heavy.

Loose or corroded connections.

Entire Electrical System Does Not Work

Blown fuse.

Loose or corroded connections.

Sulfated or worn out battery.

Dead Battery

Shorted starter solenoid.

Key switch not turned to “STOP” position.

Sulfated or worn out battery.

Battery Light Goes On When Engine Is Running

Low engine speed.

Faulty voltage regulator.

Faulty battery.

Faulty alternator.

Grounded wire in circuit.

Indicator Lights Do Not Come On In “Start” Position

Faulty bulb.

Faulty wiring.

Faulty sensor.

Battery Will Not Take A Charge

Dead cell in battery.

Loose or corroded connections.

Sulfated or worn out battery.

Fluid level low.

IMPORTANT: Avoid damage!

• Motor cables should NOT be used as a handle to lift or move motors.

• Keep cable connectors free of dirt and debris.

• Clean connectors with contact cleaner.

• Use dielectric grease on all non-sealed electrical connections before connecting. Do not use any other lubricant

Slow Reel Speed - All Cutting Units

Adjust reel speed control.

Reels too tight against bed knife.

Poor connection in connector between potentiometer and harness.

Poor connection between harness and right-side motor controller.

Failed or disconnected speed control.

Power and signal wires too close together on frame cross tube.

Belt or pulley contacting gear case cover.

Slow Reel Speed - One or Two Cutting Units

Open speed control circuit between interlock module and reel motor control module(s).

Reels too tight.

Belt or pulley contacting gear case cover.

Left and Right Reels Rotating in Wrong Direction

Left and right reel motor cables connected to wrong connectors.

Left and right motor cables or connectors connected to wrong motor.

Right Reel Rotating in Wrong Direction

Poor connection between switch and control harness.

Poor connection between control harness and right-side controller.

Left and Center Reels Rotating in Wrong Direction During Backlap

Forward/reverse switch connector disconnected.

Forward/reverse switch failed in reverse position.

Poor connection between switch and control harness.

All Cutting Units Not Operating Correctly

Mow solenoid connector poor connection.

Mow-transport switch connector poor connection.

Mow-transport switch failed.

48-volt power cable terminals poor connection.

Ground cables terminals poor connection.

48-volt alternator failed.

Improperly adjusted brake or mow-transport switch.

Poor connection in wire from interlock module to motor control harness.

Low voltage from 48-volt alternator or poor connections.

Cutting Unit Fails to Operate

Motor connectors poor connection.

48-volt power cable terminals poor connection.

Ground cables terminals poor connection.

Motor failed.

Motor controller failed.

Belt broken.

Drive pulley loose.

Improper drive spline connection.

Damaged motor or controller wires.

Reel Motors Stopping or Operating Erratically

Motor cable connectors poor connection.

Motor cable connectors contaminated.

Motor wires damaged.

Ground cables terminals poor connection.

Brake switch or linkage needs adjustment.

Slow Reel Speed

Oil level low. (See Checking Hydraulic Oil Level in SERVICE TRANSMISSION section.)

Oil overheats.

Wrong oil.

Adjust reel speed on backlapping valve.

Reels too tight against bed knife.

Backlapping valve inlet screen clogged.

Dirty relief valve.

Worn or stuck relief valve.

Worn pump or motor(s).

Reel Motors Stopping or Operating Erratically

Brake switch or linkage needs adjustment.

Oil Overheats

Low oil level.

High ambient temperatures working under heavy loads.

Dull cutting reels.

Cutting reels adjusted with interference.

Park brake locked.

Wrong oil.

Dirty oil.

High-pressure internal leak.

Foaming Oil

Trapped air after repairs.

Low oil level.

Wrong oil.

Water in oil.

Air leaks.

Noisy Pump

Low oil level.

Air leaks on suction side.

Hydraulic System Fails to Function

Wrong oil.

Low oil level.

Clogged suction line.

Air leaks.

Faulty relief valve.

Faulty pump or motor(s).

Machine Will Not Move Forward Or Backward

Low oil level.

Wrong Oil.

Control linkage out of adjustment.

Park brake not disengaged.

Forward/reverse cable broken.

Low charge pressure.

Internal pump damage.

Noisy System

Low oil level.

Air in system.

Oil filter plugged.

Internal pump or motor damage.

Park brake locked.

Cutting reels adjusted improperly.

Accelerates Slowly

Low oil level.

Control linkage loose or out of adjustment.

Air in system.

Low charge pressure.

Park brake locked.

Machine Moves With Engine Running And Hydrostatic Control Pedals In Neutral

Creep linkage out of adjustment.

Pedals Do Not Return To Neutral

Spring out of adjustment.

Reel Controller Diagnostic Light Flashes One Time

• Motor Failed To Start

Cutting Unit not turning freely.

Bedknife to reel adjusted too tight.

Reel drive system not turning freely.

Poor connection in 3-wire motor connector.

Poor connection in 6-wire motor connector.

Reel motor malfunction.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Two Times

• Motor Stops During Operation

Cutting reel jammed by debris.

Reel drive system not turning freely.

Poor connection in 6-pin connector.

Broken or damage wires between motor and controller.

Reel motor malfunction.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Three Times

• Motor Moves But Fails To Start

Cutting reel jammed by debris.

Broken or damage wires between motor and controller.

Reel motor malfunction.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Four Times

• 48-volt Alternator Output Voltage Is Over 68 Volts

Poor connections on alternator or alternator harness.

Alternator malfunction.

Reel Controller Diagnostic Light Flashes Five Times

• 48-volt Alternator Output Voltage Is Below 28 Volts

Engine speed too low.

Bedknife to reel too tight.

Verticutter too deep.

Dull reel and bedknife.

48-Volt alternator belt slippage.

Poor connection on 48-volt power or ground connections.

Poor connection on 12-volt alternator.

Alternator malfunction.

Reel Controller Diagnostic Light Flashes Six Times

• Potentiometer Voltage Low

Poor connection between right controller and speed control potentiometer.

Damaged wires between right controller and speed controller potentiometer.

Reel Controller Diagnostic Light Flashes Seven Times

• Potentiometer Voltage Too High

Poor connection in reel motor speed control.

Potentiometer malfunction

Right reel motor controller malfunction.

Reel Controller Diagnostic Light Flashes Eight Times

• Cutting Unit Stops

Poor connection on 3-pin connector

Damaged wires on 3-wire harness between motor and controller.

Reel motor malfunction

Controller malfunction

Reel Controller Diagnostic Light Flashes Nine Times

Damaged wires in 3-Wire harness.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Ten Times

Bedknife to reel too tight.

Verticutter too deep.

Dull reel and bedknife.

Reel drive system malfunction.

Damaged wire in 6-wire harness between reel motor and controller.

Reel motor malfunction.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Eleven Times

Cutting reel jammed by debris.

Broken or damage wires between motor and controller.

Reel motor malfunction.

Controller malfunction.

Reel Controller Diagnostic Light Flashes Thirteen Times

• While Moving From Mow-transport Lever Into Mow Transport

Damaged 3-wire harness.

Reel motor malfunction.

Controller malfunction.

Poor Cut: Jagged Cut Quality or Browning

Bed knife to reel out of adjustment.

Reel dull.

Bed knife dull.

Poor Cut: Marcelling or Hop

Ground speed too high or engine rpm too slow (not at rated 3350 ± 50 rpm).

Poor Cut: Streaked Appearance

Bed knife and/or reel grooved, ribbed, or rifled due to reel-to-bed knife adjustment too tight or running machine without grass in the reels.

Backlap valve reel speed adjustment too slow

Grass Buildup On Rolls

Scraper out of adjustment.

Mowers Will Not Raise/lower

Failed hand switch.

Broken or shorted wiring.

Not enough oil in reservoir.

Defective solenoid.

Control valve spool does not move.

Pump does not rotate.

No output from pump.

Reels Will Not Rotate

Reels too tight against bed knife.

Mow/transport lever not engaged.

Mow/transport lever not engaged.

Cutting reels plugged.

Not enough oil in reservoir.

Hydraulic pump not rotating.

Broken or shorted wiring.

Defective solenoid.

Control valve spool does not move.

No output from pump.

Mower Reels Squeal

Operating reel without grass (Grass clippings lubricate cutting reel and bed knife).

Improper bed knife to reel adjustment.

Cutting Reels Operating In Reverse

Backlapping valve engaged.

Cutting reel motor hoses reversed.

Oil Leaks From Cutting Unit Motor

Motor seal leaks.

Loose fittings.