Melbourne boating centres on Port Phillip, with Western Port to the south-east and river berths along the Yarra. It is a large, shallow bay that builds a short steep chop quickly in a southerly — which has more to do with engine wear than owners expect.
What local conditions do to an engine
Bay chop means engines work hard in short bursts, and it stirs tank sediment. Boats that motor comfortably in flat water often block a fuel filter on the first rough crossing of the season, because the contamination was always there and finally got shaken loose. Carry spare filters and know how to change and bleed them.
The colder season here produces a real lay-up pattern: many boats sit for months. That is when coolant condition, oil left dirty over winter, and moisture in tanks do their damage. An engine put away with fresh oil and a full tank is in far better shape in spring than one shut down and forgotten.
Cooler water gives more cooling margin than the tropics do, so an overheating fault here is rarely marginal capacity — it usually means genuine restriction or a failed component. Treat it as a fault to find, not a condition to live with.
Finding the right technician
Winter is the sensible time to book non-urgent work, and the busy pre-summer window is not. Yards fill from roughly September, so a repower or gearbox job planned in July gets a better slot and often better attention than the same job requested in November.
Ask whether the technician works on your engine family regularly, what the quote includes, and who is responsible for commissioning and a sea trial afterwards.
Before you call
Note the conditions when the fault appears — under load, in chop, after refuelling, only when warm. On Port Phillip, "only when it's rough" is a strong clue pointing at fuel supply rather than the engine itself.