Cummins/Onan — Adjusting the Pump Belt Tension
Adjustments · Sea water pump belt
From a Cummins/Onan operator's manual covering: MDL3, MDL4, MDL6. Check it applies to your exact model before use.
Applies to: Cummins/Onan MDL3, Cummins/Onan MDL4, Cummins/Onan MDL6, Cummins/Onan 3A1.7 engine, Cummins/Onan 4A2.3 engine, Cummins/Onan 6A3.4 engine
Before you start
- Accidental starting of the generator set can cause severe personal injury or death; disconnect starting battery cables (negative first) before service.
Procedure
- Remove battery cables (negative cable first) and remove belt guard.
- Inspect belt for ply separation, fraying and glazing; replace if any condition exists.
- Measure belt tension with a belt tension tool; should be 60 pounds (267 N).
- Loosen bolt through elongated slot in sea water pump bracket and slide pump until proper tension is secured.
- Reinstall belt guard; do not operate genset without belt guard in place.
Tools required
- belt tension tool Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Belt tension 60 pounds (267 N)
Full service-parts list: Cummins/Onan MDL3 →, Cummins/Onan MDL4 →, Cummins/Onan MDL6 →
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.