Yamaha G1A and G1E Wiring Troubleshooting Diagrams 1979-89

Yamaha’s premiere cart in 1979 was the G1A Model J10 Gas-powered vehicle that featured an Autolube Oil Injection System to supply oil to the engine in precise oil-to-gas ratios. This eliminated the premixing of the oil and gas and improved combustion, oil consumption, and carbon buildup. In 1980, Yamaha introduced the G1E 36 volt Electric J14 series. 

The following diagrams are for ease of tracing out circuits and pinpointing points of failure in the Yamaha G1A and G1 E.

G1 Gasoline Carts

The first Generation Gas Carts had solenoids (or relays) that had all terminals on one end of the unit. These solenoids are no longer available and are replaced with a model with terminals on both ends. The replacement for the gas cart is a 12-volt model.

Retrofit for this solenoid is shown in the illustration below.

G1A,A2,A4,A5 Gas 1979-81, 1983-89

G1A3 Gas 1982

SYMPTOM
POSSIBLE CAUSE
CORRECTIVE STEPS
Engine Will Not Turn OverBattery is not chargedTest and recharge
Poor terminal connectionClean and tighten
Bad starter motorTest, repair or replace
Engine Turns Over, Will Not StartMoisture on ignition wires and spark plug capWipe wires and cap clean and dry
Faulty ignition cablesReplace any cracked or shorted cables
Open or shorted primary ignition circuitTrace primary ignition circuit and repair as necessary
Faulty coilTest and replace if necessary
Dirt or water in fuel line or carburetorClean lines and carburetor. Replace filter
Faulty fuel pumpInstall new fuel pump
Carburetor flooded or carburetor float setting incorrectAdjust float level - check seats
Loss of PowerDirt or water in fuel line, carburetor or filter.Clean lines, carburetor and replace filter
Incorrect ignition timingReset timing
Dirty or incorrectly gapped spark plugClean plug and set gap - replace if neccessary
Engine StallsIncorrect choke adjustmentAdjust choke
Idle speed set too lowAdjust idle speed on choke
Incorrect carburetor float settingAdjust float setting
Faulty ignition wiringTrace out and correct
Dirty or incorrectly gapped sparkClean plug and set gap
Contaminates in fuel line or carburetorClean lines, carburetor and replace filter
Faulty CoilCheck and replace

G1 Electric Carts

The first generation electric cart had solenoids (or relays) that had all terminals on one end of the unit. These solenoids are no longer available and are replaced with a model with terminals on both ends.

Below is the retrofit for replacing these with a contemporary solenoid.

G1E 1980-86

Item List

  1. Batteries 6x6v
  2. Solenoid Relay
  3. Speed Controller
  4. Resistor Coil
  5. Traction Motor
  6. Charge Receptacle
  7. Back Up Buzzer
  8. Stop Switch (at pedal)
  9. 10 amp Fuse
  10. 10 amp Fuse

The wiper arm is at full rest and making contact with Contact Terminal #1. 

  • Key switch –  Off
  • Speed Controller –  At Contact #1
  • Forward Solenoid – Not Energized
  • Reverse Solenoid – Not Energized
  • Voltage to Motor – None
  • Voltage across A1 and A2 – None
  • Voltage across F1 and F2 – None
  • Stop Switch – In Open state

Power Flow Logic Diagram – Forward 1st Speed

First Speed -the wiper arm is making contact with Contact Terminal #1 and pedal is slightly pressed. 

  • Key switch –  Forward
  • Speed Controller –  At Contact #1
  • Forward Solenoid – Energized
  • Reverse Solenoid – Not Energized
  • Voltage to Motor – Present
  • Voltage across full resistor
  • Stop Switch – In closed state

Power Flow Logic Diagram – Forward 2nd Speed

Second Speed – the wiper arm is making contact with Contact Terminal #2. 

  • Key switch –  Forward
  • Speed Controller –  At Contact #2
  • Forward Solenoid – Energized
  • Reverse Solenoid – Not Energized
  • Voltage to Motor – Present
  • Voltage across 4/5 of resistor
  • Stop Switch – In closed state

Power Flow Logic Diagram – Reverse 2nd Speed

Second Speed Reverse – the wiper arm is making contact with Contact Terminal #2. 

  • Key switch – Reverse
  • Speed Controller –  At Contact #2
  • Forward Solenoid – Not Energized
  • Reverse Solenoid – Energized
  • Voltage to Motor – F1 and F2 flow reversed
  • Voltage across 4/5 of resistor
  • Stop Switch – In closed state
  • Reverse buzzer – Energized

G1E Controller Exploded View

Troubleshooting Chart

SYMPTOM
POSSIBLE CAUSE
CORRECTIVE STEPS
Motor Will Not TurnMotor terminals are loose or corroded.Tighten or clean tereminals
Brushes not contacting the commutatorAdjust
Lead wires faultyCheck continuity, test, repair or replace
Field coil brokenRepair or replace
Armature coil brokenRepair or replace
Motor Turns SlowlyTerminals loose and/or corrodedCheck terminals, clean and tighten
Accelerator arm movement restrictedAdjust linkage
Leads partially broken or looseCheck for loose wire strands, replace if defective, tighten connection
Bearings Overheating PowerBearings worn or low on greaseReplace
Bearings not installed correctlyAdjust bearings
Noisy motor operationMounting bolts looseTighten mounting bolts
Bearing failureReplace
Bearings dirtyReplace
Bearings run out of greaseReplace
Dirt or foreign material in motor caseClean motor
Motor VibrationArmature out of roundReplace
Motor mounting bolts looseRetighten

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