Winter on the Sunshine Coast is not brutal, but it is wet, and wet is what kills engines that sit. Water finds its way into fuel, corrosion starts where salt was never rinsed off, and the boat you left running fine in October will not start in April.
The first job is fuel. We stabilize what is in the tank, run the engine long enough to get treated fuel through the whole system, and drain the carburetor bowls on anything that has them. Untreated ethanol fuel sitting for four months is the single most common reason a spring start goes badly.
Second is water. We flush the engine with fresh water, fog the cylinders, and change the gear oil. Milky gear oil in the fall tells you a seal is already leaking, and finding that in November is much cheaper than finding it in May.
Third is the outside of the engine. Rinse, dry, grease every fitting, and check the anodes. Anodes are cheap. The parts they protect are not.
If you want it done properly, book it before the end of October. We get busy the week everyone realizes the season is over.
