Onan 850-0040 Water Pump Lock Washer
The Onan 850-0040 Water Pump Lock Washer is the washer specified for this position in the Onan pump. Thickness, bore and outside diameter all matter, because the washer is part of the stack height that sets how far the fastener pulls the joint down.
Because it costs so little, this is a part worth renewing as a matter of course during any pump rebuild rather than reusing something that has already taken its set. It also removes the risk of finding you are one washer short partway through the job. This part is listed for Onan water pumps 132-0115 and 132-0251 on MDJF 15 kW generator sets.
Key Features
- Correct bore, outside diameter and thickness for its position
- Spreads fastener clamping load and protects the surface beneath
- Maintains joint clamp under vibration and thermal cycling
- Direct replacement for the original Onan part
- Cheap to keep as a spare alongside pump fasteners
Applications
- Raw water pump service on Onan marine generator sets
- Reassembly after an impeller, cover or bearing change
- Replacing corroded or flattened original washers
- Building a pump spares kit for the season
Specifications
- Brand: Onan
- Manufacturer Part Number: 850-0040
- Part Type: Lock Washer
- Fits: Onan water pumps 132-0115 and 132-0251 on MDJF 15 kW generator sets
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 0.02 lb
Frequently Asked Questions
Q: How many should I buy?
Most owners order a small surplus, since these are easy to drop into a bilge and awkward to source in a hurry.
Q: Can I reuse a lock washer?
It is a false economy. Once compressed it has lost its spring and will not stop the fastener backing off.
Q: Does washer thickness matter?
Yes. It is part of the clamped stack height, so a thicker or thinner washer changes how far the fastener pulls the joint down.
Q: Which way round does it go?
Plain washers can go either way. If the original was dished or toothed, match its orientation as it came out.
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 lock washer.
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