Onan 131-0220 Water Pump Seal Assembly
The Onan 131-0220 Water Pump Seal Assembly seals the pump shaft where it passes out of the wet end. It is a wearing part by design, because it depends on a thin film of pumped water for lubrication, and that same water carries the salt and fine grit that eventually wear its sealing face away.
A seal that has started to pass water rarely recovers. Salt builds on the face, the leak gets worse under load, and the bearing behind it begins to suffer long before anything sounds wrong. Renew the seal whenever the pump is opened far enough to reach it, and renew the bearings too if the seal has been leaking for a while. This part is listed for Onan water pump 131-0257 (casting 170-3172) on MCCK 4.0 and 6.5 kW and MDJE 7.5 kW generator sets.
Key Features
- Sized to the Onan pump shaft diameter and seal bore
- Keeps sea water out of the bearing housing and drive end
- Direct replacement for the original seal, no machining required
- Serviced as part of a normal pump rebuild
- Protects the shaft, bearings and pump body from salt water damage
Applications
- Raw water pump rebuilds on Onan marine generator sets
- Curing a drip or salt crust at the pump weep hole
- Service following a dry running episode
- Overhaul alongside the bearings, shaft and impeller
Specifications
- Brand: Onan
- Manufacturer Part Number: 131-0220
- Part Type: Seal Assembly
- Fits: Onan water pump 131-0257 (casting 170-3172) on MCCK 4.0 and 6.5 kW and MDJE 7.5 kW generator sets
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 0.1 lb
Frequently Asked Questions
Q: Does dry running damage the seal?
It does. The seal relies on pumped water for lubrication, so even a short dry run can score the face.
Q: What does a leak at the weep hole mean?
It means the shaft seal is passing water. The weep hole is there to let it out before it reaches the bearings, so treat it as a service warning.
Q: Can I fit a new seal without pulling the pump apart?
Usually not. Reaching the seal normally means removing the impeller and the shaft, so plan on a full strip.
Q: Should I replace the bearings at the same time?
If the seal has been leaking for any length of time, yes. Salt water reaches them quickly and the damage is not always audible.
Not sure this is the right part? Send us a Picture of the Pump Plate on your pump and the CLR Marine team will confirm the correct seal assembly.
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