Cummins/Onan — Adjusting V-Belt Tension
Adjustments · V-belt / alternator
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKB, Kubota D1105 engine, Kubota V3300-E2B engine
Before you start
- Disconnect negative battery cable to prevent accidental starting
Procedure
- Disconnect negative battery cable
- Remove belt guard or enclosure top panel and access doors
- Loosen alternator pivot bolt first, then adjusting bracket bolt on top
- Pivot alternator out to tighten belt tension; hold with tension adjusting bolt
- Check tension by applying 20 lbs (10 kg) to middle of pulley span; correct deflection is 3/8 inch (10mm)
- Tighten alternator bolts when tension is correct
- Tighten bolts, secure belt guard/enclosure, reconnect battery cables negative last
Specs & values
- deflection 3/8 inch (10 mm) at 20 lbs (10 kg)
Full service-parts list: Cummins/Onan MDKB →, Kubota D1105 engine →, Kubota V3300-E2B engine →
Source: Cummins/Onan operator's 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.