Generac — GV410 Starter Pinion Jam Procedure
Testing & diagnosis · Starter / flywheel ring gear
From a Generac service manual covering: 4077, 4079, 4109, 4389, 4390, 4456, 4674, 4675. Check it applies to your exact model before use.
Applies to: Generac 4077, Generac 4079, Generac 4109, Generac 4389, Generac 4456
Before you start
- New rubber bumper gets placed at base of block right above sump cover, and on the centerline of the starter.
Procedure
- Measure the voltage at the starter contactor terminal; verify 11-12 volts DC during cranking.
- If below 11 volts DC, measure at the battery terminals during cranking; recharge/replace battery if below 11 volts DC.
- If battery voltage is above 11 volts DC, check for proper battery cable sizing.
- Manually engage the starter pinion into the ring gear and check for .020-.035 inch backlash, measuring at eight equally spaced locations.
- Shim or remove shims as necessary using shim kit part number 0D4791.
- Visually check that the starter motor is perpendicular to the ring gear; replace the starter motor if the mounting bracket is bent.
- Check position of rectangular rubber bumper part number 0C3794; older units used rubber dimples and should be replaced.
Tools required
- Feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
Full service-parts list: Generac 4077 →, Generac 4079 →, Generac 4109 →, Generac 4389 →, Generac 4456 →
Source: Generac 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.