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Home›Repair guides›Perkins›Electric Starting System - Test

Perkins 1103 / 1104 — Electric Starting System - Test

Testing & diagnosis

For the Perkins 1103 / 1104, from the Perkins service manual.

Applies to: Perkins 1103, Perkins 1104, Perkins 1104 (1103 also covered) engine

Before you start

  • Do not crank the engine for more than 30 seconds. Allow the starter to cool for two minutes before cranking again.

Procedure

  1. Measure the battery voltage across the battery posts while cranking. Compare with expected cranking voltage table.
  2. Measure the current sent to the starting motor solenoid from the positive battery post with an ammeter.
  3. Measure the voltage of the starting motor while cranking and compare with the temperature range table.
  4. Measure voltage drops in the cranking circuits and compare with the maximum acceptable voltage drop table.
  5. Rotate the crankshaft by hand to ensure it is not stuck; check oil viscosity and external loads.
  6. Attempt to crank the starting motor; if it cranks slowly remove for repair or replacement.
  7. If the starting motor does not crank, check for blocked engagement of the pinion gear and flywheel ring gear.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Specs & values

  • Cranking voltage 12 volt system: 6-8 V at -23 to -7 °C, 7-9 V at -7 to 10 °C, 8-10 V at 10 to 27 °C.
  • Cranking voltage 24 volt system: 12-16 FridayParts $159.99 V at -23 to -7 °C, 14-18 Amazon eBay FridayParts $389.00 V at -7 to 10 °C, 16-24 Amazon eBay V at 10 to 27 °C.
  • Maximum voltage drop battery post '-' to starting motor terminal '-': 0.7 V (12 V), 1.4 V (24 V).
  • Maximum voltage drop across the disconnect switch: 0.5 V (12 V), 1.0 V (24 V).
  • Maximum voltage drop battery post '+' to solenoid '+': 0.5 V (12 V), 1.0 V (24 V).
  • Maximum voltage drop solenoid 'Bat' to 'Mtr': 0.4 V (12 V), 0.8 V (24 V).

Full service-parts list: Perkins 1103 →, Perkins 1104 →

Source: Perkins service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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