Updated October 26, 2026
How surveys describe it
Wording varies by surveyor. Illustrative examples (not quoted from any real survey):
- “Impeller service history unknown; recommend replacement.”
- “Low raw-water flow observed at the exhaust.”
What it is
The raw-water pump's rubber impeller pushes cooling water through the engine. It wears and is replaced as routine maintenance.
How serious it is
Cheap to replace, but a failed impeller can overheat an engine quickly. Owner-reported shop bills range from under $200 to over $400 depending on access.[1]
In our reports this usually lands under Watch. Your survey's details decide.
What it typically costs
| Scope | Estimated range |
|---|---|
| 1 engine | $200–$500 |
| 2 engines | $400–$1,000 |
These are whole-job ranges drawn from published figures.[1]
- Routine service
- Some sterndrives require pulling the drive, which costs more
Estimates to help you frame a conversation with a yard, not quotes. Real prices depend on the boat, the yard, access and what's found once work starts. Confirm with your surveyor or a qualified yard.
What to ask your surveyor or yard
- When was it last replaced?
- Does this drive need to come off to reach it?
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- Approx. price to replace impeller, iboats forums (owner reports). Boat owners' reported prices. Accessed 2026-10-26.