Sea Water Pump Repair Kit 121575-42000 721575-42702 for Yanmar 2QM 3QM 2GM 3GM 3HM Impeller
Sea Water Pump Repair Kit 121575-42000 721575-42702 for Yanmar 2QM 3QM 2GM 3GM 3HM Impeller
Product Overview
Sea water pump repair kit for Yanmar marine diesels, the full rebuild set for the raw water pump on the 2QM, 3QM, 2GM, 3GM and 3HM engines. It is the kit for pump 121575-42000 and 721575-42702 and it includes the impeller, the 15 mm bore bearings, seals, cam and the cover screws, everything that wears in a pump of this age.
The impeller inside crosses to Jabsco 22799-0001 and to Yanmar 124223-42090, -42091 and -42092, and the same impeller is sold under Sierra 23-2003, Sierra 18-8950, Kohler 229955, Vetus IMP00101 and Ancor J050016. On a Yanmar the pump is usually behind the engine, driven off the front of the crankcase, so the whole job is done by feel as much as by sight.
Rebuilding rather than replacing matters here: a new bare pump costs many times what this kit costs, and the pump body on a Yanmar is a solid bronze casting that outlives two or three impellers. The parts that actually fail are the lip seal, the bearings and the cam, and all three are in the box.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Raw water pump repair kit |
| Fits | Yanmar 2QM, 3QM, 2GM, 3GM, 3HM |
| Pump Numbers | 121575-42000, 721575-42700, 721575-42701, 721575-42702 |
| Contents | Impeller, gasket, bearings, seals, key, cam and screws |
| Bearings | 15 mm bore x 35 mm outside x 11 mm wide |
| Net Weight | 220 g including packaging |
| Quantity | 1 complete kit |
OEM Cross Reference
| Brand | OEM Part Numbers |
|---|---|
| Yanmar, pump | 121575-42000 |
| Yanmar, pump | 721575-42700, 721575-42701, 721575-42702 |
| Yanmar, impeller | 124223-42090, 124223-42091, 124223-42092 |
| Yanmar, impeller | 128296-42040, 128296-42070 |
| Jabsco | 22799-0001, 22799-0001-P |
| Sierra | 23-2003, 18-8950 |
| Kohler | 229955, 250872, 252475 |
| Vetus | IMP00101 |
| Ancor | J050016 |
| CEF | 500129 |
| DJ | 08-37-0601 |
Compatible Engines
| Engine | Type | Note |
|---|---|---|
| 2QM | Marine diesel, two cylinder | Raw water pump rebuild |
| 3QM | Marine diesel, three cylinder | Same pump family |
| 2GM | Marine diesel, two cylinder | Common in small yachts |
| 3GM | Marine diesel, three cylinder | Same kit |
| 3HM | Marine diesel, three cylinder | Check the pump number on the cover |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Water pump impeller | Number not listed, crosses to Jabsco 22799-0001 | 1 |
| Gasket | Included, number not listed | 1 |
| Bearings | Included, numbers not listed | 2 |
| Lip seal | Included, number not listed | 1 |
| Slinger | Included, number not listed | 1 |
| Retaining rings | Included, numbers not listed | 2 |
| Cover screws | M4, included, numbers not listed | 6 |
| Key | Included, number not listed | 1 |
| Cam | Included, number not listed | 1 |
| Cam screw and washer | Included, numbers not listed | 1 |
Why the Pump Needs a Kit, Not Just an Impeller
| Part | What It Does | If It Is Reused |
|---|---|---|
| Impeller | Moves the raw water | Set vanes, weak flow |
| Lip seal | Keeps sea water out of the bearings | Water in the bearing, pump seizes |
| Bearings | Carry the shaft | Whine and play, then a wrecked shaft |
| Cam | Shapes the vane path inside the pump | Worn cam, impeller under-pumps |
| Gasket | Seals the two pump halves | Air drawn in, pump loses prime |
| Screws and key | Hold the cover and drive the impeller | Weeping cover, slipping impeller |
Yanmar Raw Water Pump Symptoms
| What You See | What It Means | What To Do |
|---|---|---|
| Weak exhaust water at idle | Impeller set or cam worn | Kit, not just the impeller |
| Water dripping from the pump body | Lip seal failed | Kit with the seal and bearings |
| Whine from the front of the engine | Bearings dry | Kit before the shaft is damaged |
| Hot exhaust and a hot engine | Pump not moving water | Check the strainer, then the kit |
| Rubber pieces in the strainer | Vanes breaking up | Kit and flush the pipework |
| Impeller fails every season | Cam and cover worn | Kit with the cam and the seal |
Working on a Yanmar Pump
| Area | What Matters | Note |
|---|---|---|
| Access | Pump sits low on the front of the engine | Drain the sea water first |
| Cover screws | Small and easy to drop | Count them out and back in |
| Shaft wear | A scored shaft needs replacing | Check under the seal |
| Cam | Fitted with a screw and washer | The kit has both |
| Bleeding | The pump will not self prime dry | Run on muffs or in the water |
| Strainer | Dirt kills a new impeller quickly | Clean it while the pump is off |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | Standard |
| Packaging | Sealed retail packaging |
Before You Buy
- Check the number on the old pump, 121575-42000 and 721575-42702 interchange
- Fits Yanmar 2QM, 3QM, 2GM, 3GM and 3HM marine diesels
- The impeller crosses to Jabsco 22799-0001 and Sierra 23-2003
- This is the repair kit, the pump body is not included
- Check the shaft for wear under the seal before rebuilding
- Clean the sea water strainer at the same time
- 30-Day Easy Returns
- Ships from our warehouse with tracking
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Boat Owners' Review
Before You Buy
Frequently Asked Questions
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We offer a 14-day hassle-free return on all products. Items must be unused and in original packaging. Every XRmarine part is also covered by our 1-year warranty against manufacturing defects. If something is not right, email us at info@xrmarineparts.com — replacement or full refund, your choice.
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