Water Pump Repair Kit 47-803748 334-65021-0 for Mercury Tohatsu 9.9 15 18 20 HP Outboard
Water Pump Repair Kit 47-803748 334-65021-0 for Mercury Tohatsu 9.9 15 18 20 HP Outboard
Product Overview
Water pump repair kit for Mercury 9.9 to 20 HP four stroke outboards, including BigFoot and EFI models, and Tohatsu and Nissan 9.9 to 20 HP two and four stroke outboards, with a 41.2 mm eight blade impeller, 23.8 mm high, 14.0 mm hub, supplied with housing gaskets and a drive key, replacing 47-803748, 334-65021-0 and 18-8921.
Mercury and Tohatsu build these 9.9 to 20 HP motors on the same platform, so the pump is common to both and the same kit is sold under two number families. The kit carries the gaskets and the key as well as the impeller, because the housing gaskets are what fail on these pumps once they have been apart, and the key is small enough to be lost on removal.
The 41.2 mm body with a 14 mm hub and 8 blades is the mid size impeller for this range. The smaller 2 to 3.5 HP kit is 33.6 mm, so it cannot be confused once measured. Check the hub and the key, then check the housing liner and wear plate for scoring before refitting, because a scored liner lets water past the blade tips and the motor runs hot at speed.
Specifications & Attributes
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Water pump repair kit |
| Drive Type | Key drive |
| Blades | 8 |
| Outer Diameter | 41.2 mm / 1.62 in |
| Height | 23.8 mm / 0.94 in |
| Hub Shaft Diameter | 14.0 mm / 0.55 in |
| Material | Neoprene |
| Hub Material | Hardened nylon |
| Kit Parts | Impeller, housing gaskets, drive key |
| Net Weight | 33 g |
| Country of Origin | Taiwan |
OEM Cross Reference
| Brand | Part Numbers |
|---|---|
| Mercury | 47-803748, 47-803748002, 47-8M0135803, 8M0135803, 8M0214944 |
| Mercury | 8M0135821, 8M0137849, 8M0134484 |
| Tohatsu | 334-65021-0, 334650210, 334650210M, 3LD-65021-0, 3LD650210 |
| Tohatsu | 362873221M, 362-87322-1, 3RS-87322-1, 3RS-87322 |
| Nissan | 334-65021-0, 3LD-65021-0 |
| Evinrude / Johnson / OMC | 5040046 |
| Sierra | 18-8921 |
Compatible Engines
| Brand | Model or Horsepower | Stroke | Note |
|---|---|---|---|
| Mercury | 9.9 HP BigFoot | Four stroke | JPN 0R042475 and up, BEL 0P325500 and up |
| Mercury | 15 HP 351cc | Four stroke | Serial 0R235949 to 0R833819 |
| Mercury | 20 HP 351cc | Four stroke | Serial 0R235168 to 0R833819 |
| Mercury | 10 HP | Four stroke | 10HP EFI four stroke |
| Mercury | 9.9, 10, 15 and 20 HP EFI | Four stroke | Four stroke EFI range |
| Tohatsu | MFS9.9, MFS15, MFS18, MFS20 | Four stroke | MFS four stroke range |
| Tohatsu | M9.9, M12, M15, M18 | Two stroke | M two stroke range |
| Tohatsu | NSF9.9B, NSF9.9B2, NSF9.9C | Four stroke | 9.9 HP four stroke |
| Tohatsu | NSF15B, NSF15B2, NSF15C | Four stroke | 15 HP four stroke |
| Tohatsu | NSF18B, NSF18B2, MFS18B, MFS18B2 | Four stroke | 18 HP four stroke |
| Tohatsu | NSF20C, MFS20C, MFS9.9E, MFS15E, MFS20E | Four stroke | 20 HP and EFI models |
| Tohatsu | NS9.9C, NS9.9D2, M9.9C, M9.9D, M9.9D2 | Two stroke | 9.9 HP two stroke |
| Tohatsu | NS15C, NS15D2, M15C, M15D2 | Two stroke | 15 HP two stroke |
| Tohatsu | NS18D, NS18E2, M18D, M18E2 | Two stroke | 18 HP two stroke |
| Nissan | NS9.9, NS15, NS18 | Two stroke | Same pump as the Tohatsu models |
| Nissan | NSF9.9, NSF15, NSF18, NSF20 | Four stroke | Same pump as the Tohatsu models |
Pump Numbers Covered
| Number | Where It Appears |
|---|---|
| 47-803748, 47-803748002 | Mercury impeller kit |
| 47-8M0135803, 8M0135803 | Mercury current number |
| 8M0214944 | Mercury four stroke EFI kit |
| 8M0135821, 8M0137849, 8M0134484 | Mercury kit supersessions |
| 334-65021-0, 334650210M | Tohatsu and Nissan impeller |
| 3LD-65021-0, 3LD650210 | Tohatsu current format |
| 362873221M, 362-87322-1, 3RS-87322-1 | Tohatsu kit supersessions |
| 5040046 | Evinrude Johnson OMC equivalent |
| 18-8921 | Sierra aftermarket equivalent |
What's Included
| Component | Qty |
|---|---|
| Water pump impeller, 8 blade | 1 |
| Housing gaskets | 2 |
| Impeller key | 1 |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | Standard |
| Packaging | Sealed retail packaging |
Before You Buy
- Check the number on the old impeller, 47-803748 and 334-65021-0 are the same 41.2 mm body
- Check the diameter, this is the 41.2 mm kit, not the 33.6 mm kit for the 2 to 3.5 HP motors
- Check the hub, this is the 14.0 mm body
- Check the serial number against the ranges above, Mercury changed the pump across the range
- Check the housing liner and wear plate for scoring before refitting
- Fit with glycerine or soap only, never grease or oil on neoprene
- Seat the key, fold the blades with rotation, then both gaskets and the housing
- Run on muffs and confirm the telltale before leaving the ramp
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