Onan 132-0305 Water Pump Cam
Inside the raw water pump, the Onan 132-0305 Water Pump Cam forms the high spot in the bore. As the impeller turns, each vane rides up onto the cam, collapses, and then springs back open on the far side to pull in the next charge of water. The height and profile of the cam set both the displacement of the pump and how hard the impeller has to work.
Because it is clamped rather than pressed in, a cam can also work loose. A cam that shifts in the housing chews impeller vanes, so check that the screw is tight and that the cam face is still flush with the bore when you are in there. Replace the cam if its edge is rounded, pitted or has a wear step where the vanes cross it. This part is listed for Onan water pump 132-0284 on MAJB 2.5 and 3.0 kW generator sets.
Key Features
- Eccentric profile machined to the Onan pump housing bore
- Forms the seal between the inlet and discharge sides of the pump
- Compresses the impeller vanes to expel water at the discharge port
- Clamped installation with the original cam screw, no pressing required
- Restores dry priming and rated flow when the old cam edge is worn
Applications
- Raw water pump overhauls on Onan marine generator sets
- Repairing a pump that primes slowly or will not lift water after layup
- Service alongside a new impeller and wearplate
- Correcting impeller vane damage caused by a loose or worn cam
Specifications
- Brand: Onan
- Manufacturer Part Number: 132-0305
- Part Type: Cam
- Fits: Onan water pump 132-0284 on MAJB 2.5 and 3.0 kW generator sets
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 1 lb
Frequently Asked Questions
Q: Do I have to replace the cam with every impeller?
No, but inspect it every time. Replace it whenever the impeller has been run dry or has lost a vane.
Q: Will a new cam alone restore flow?
Only if the cam was the fault. Check the wearplate and cover gasket at the same time, since all three share the sealing job.
Q: How do I check the cam for wear?
Look along the edge the vanes climb. A sharp, square edge is good. A rounded edge or a polished step where the vanes cross means it is worn.
Q: Does the cam screw need sealing?
If the screw passes through into the wet side of the housing it does. Use a fresh sealing washer or thread sealant as originally fitted.
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 cam.
CLRMarine
