A hull surveyor will tell you whether a used boat is structurally sound. They rarely tell you whether the engine has another season left in it or another decade. A pre purchase engine inspection is a separate job, and it pays for itself many times over.
Why hours alone mislead
Two engines with 2,000 hours can be in very different condition. One that has been serviced annually and run regularly will outlast one that sat for a decade with old oil and no use. Condition matters more than the hour meter.
What a proper inspection covers
- Visual inspection of the engine bay, looking for oil weeps, coolant trails, exhaust soot, and corrosion.
- Compression test or cylinder balance check, depending on engine type.
- Oil sample sent for analysis. This tells you about wear metals, fuel dilution, and coolant ingress.
- Cold start observation, smoke colour analysis, and a full warm up.
- A river trial under load, checking temperature, oil pressure, and exhaust water flow at cruising revs.
- Inspection of the gearbox, drive train, and shaft seal.
Paperwork matters too
Ask for service records, receipts, and the engine hours log. A boat with a coherent service history is worth more than one without, and the absence of records is itself information.
Book an inspection on the Thames
Oli carries out pre purchase engine inspections across the Thames from London to Oxford. You get a written report with photos, an oil analysis result, and a clear plain English summary of what you are buying.
