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Massey Ferguson 230, 235, 240, 245, 250 - Electrical system

MF 230, 235, 240, 245, 250 Tractors Repair Operations

Testing

The electrical system on all models is 12 volt, negative grounded system. Models MF 230, 235, 245 are equipped with Delco-Remy alternator and starter motor. Massey Ferguson 240, 250 tractors may be equipped with either Lucas or Perkins (Hitachi) alternator and starter motor. Before any electrical system service is performed, a thorough check of condition of battery, cable connections, alternator drive belt and pulleys should be made. Always disconnect battery leads before performing any service operations on the tractor electrical system. Do not connect or disconnect any part of charging system while the engine is running as damage to voltage regulator could result. When connecting battery leads, booster battery or battery charger, be sure to observe correct polarity (positive to positive, negative to negative). Do not short across or ground any terminals on alternator. Do not attempt to polarize alternator.

Alternator and regulator (Massey Ferguson 230, 235, 245 testing) - A Delco-Remy alternator with integral solid state regulator is used on these tractors. Both 37 amp and 42 amp alternators are available, so be sure of model when testing. To test alternator output while installed on tractor, first disconnect battery ground cable. Connect a test ammeter and voltmeter in circuit at alternator BAT terminal. Connect a carbon pile across battery and twin on headlights. With engine operating at moderate speed, adjust carbon pile as required to obtain maximum current output. Voltage should be approximately 14.5 volts. If ampere output is within 10 amperes of rated output stamped on alternator frame, alternator is not defective. If output is not within 10 amperes of rated output, ground field winding by inserting a screwdriver into test hole in rear of alternator. If output is now within 10 amperes of rated output, renew regulator and check field (rotor) winding. If output is still not within 10 amperes of rated output, disassemble alternator and check field winding, diode trio, rectifier bridge and stator. If alternator fails to start charging at all, there may be an open circuit in wiring to No. 1 terminal of alternator. Voltage must be present at this terminal to provide initial excitation of field winding to start alternator charging. A quick field check for an open excitation circuit is to momentarily place a jumper wire between alternator BAT terminal and No. 1 terminal with engine running. If alternator starts charging, when it would not without jumper, an open excitation diode (located in wiring harness), oil pressure switch (diesel models), or ignition switch (gasoline models) is indicated.

Alternator and regulator (Models MF 240, 250 With Lucas Alternator testing) - Check alternator wiring harness continuity, disconnect wiring connections from alternator and turn start switch to auxiliary position. Connect a voltmeter between ground and each of the disconnected leads. Battery voltage should be present at the alternator + (battery) lead and the IND (warning light) lead. A zero reading indicates open circuit in wiring or faulty warning light bulb. If an additional ground lead is used on alternator, check continuity of lead using an ohmmeter. If voltage is present at + and IND leads, but warning light fails to come on when leads are reconnected to alternator, a faulty regulator and/or field (rotor) winding is indicated. To check alternator output, first disconnect battery ground cable. Disconnect wiring from alternator, remove cover from rear of alternator, then reconnect wiring leads. Connect an ammeter between starter solenoid terminal and alternator output terminal. Connect a voltmeter between output terminal and ground. Connect a carbon pile across battery terminals. Reconnect battery ground cable and start engine. Operate engine at 2000 rpm, turn on headlights and adjust carbon pile as required to obtain maximum current output. Ammeter reading should be approximately 34 amperes. Adjust carbon pile so ammeter reading is less than 10 amperes. Voltmeter reading should be within range of 13.6-14.4 volts. If output is low, use a jumper lead to short together the F and "-" connections on alternator. If output is now within specified range, a faulty regulator and/or field winding is indicated. If output is still low, fault is elsewhere in alternator.

Alternator and regulator (Massey Ferguson 240, 250 With Perkins Alternator testing) - Check alternator output, connect a voltmeter between D+ termihal of alternator and ground. Start the engme and observe voltmeter reading. Voltage should be within range of 13 to 15 volts. If voltmeter readmg exceeds 15.5 volts, voltage regulator is faulty. If voltmeter reading is less than 13 volts, insert a pin into small hole near the center of alternator rear housing to ground the F terminal. if voltage is now within range of 13 to 15 volts regulator is faulty. If voltage remains less than 13 volts, disassemble alternator and check field winding, diodes and stator.

Starting motor

Models MF 230, 235, 245 - A Delco-Remy starting motor is used on all models. Connecl voltmeter and ammeter to starting motor to perform no-load test. No-Load Test: Volts - 9, Amperes (w/solenoid) - 20-120, Rpm - 9000-14000. Starter drive pinion clearance is nol adjustable; however, some clearance must be maintained between end of pinion and starter drive frame to assure solid contact of the magnetic switch. Normal pinion clearance should be within the limits of 0.25-3.56 mm (0.010-0.140 inch). Connect a 6 volt battery to solenoid terminals when measuring pinion clearance to keep armature from turning.

Massey Ferguson 240, 250 - Lucas starting motor is used on some MF 240, 250 tractors. Connect voltmeter and ammeter to starting motor to perform no-load test. No-Load Test: Volts - 11, Amperes (max.) - 100, Rpm - 5000-7500. Brush spring tension should be between 11.6-15.5 N (42-55 ounces). Renew brushes if length is less than 8 mm (5/16 inch). When renewing armature bushings, new bushings should be soaked in engine oil for 24 hours prior to installation. Tighten the two throughbolls to a torque of 11 Nm (8 ft-lbs.). Starter drive pinion end clearance is adjustable. Connect a 6 volt battery to blade terminal on solenoid to hold pinion in engaged position. While pushing pinion lightly towards armature to remove any free play in linkage, measure clearance between end of pinion and the thrust collar. Turn eccentric pin as required to obtain recommended clearance of 0.13-0.38 mm (0.005-0.015 inch). Tighten locknut to hold pin in position.

Perkins (Hitachi) starting motor is used on some MF 240, 250 tractors. Connect voltmeter and ammeter to starting motor to perform no-load test. No-Load Test: Volts - 12, Amperes (max.) - 120, Rpm - 4000-7500. Armature commutator minimum allowable diameter is 40 mm (1.575 inches). Maximum allowable runout for armature and commutator is 0.10 mm (0.004 inch). Depth of insulation below surface of commutator should be 0.20-0.80 mm (0.008-0.031 inch). Minimum allowable brush length is 14 mm (0.551 inch). Armature end play should be 0.05-0.30 mm (0.002-0.012 inch). If end play exceeds 0.30 mm (0.012 inch), install an additional thrust washer. Starter drive pinion end clearance is adjustable. Connect 6 volt battery to solenoid S terminal to hold pinion in engaged position. Push pinion lightly towards armature to remove free play in linkage, then measure clearance between face of pinion gear and the pinion stop. Recommended clearance is 0.3-1.5 mm (0.012-0.060 inch). Add or remove spacer washers as required to obtain desired clearance.