What Is an Outboard Motor?
A complete power unit hung on the transom - the heart of small boats and tenders, a motor that lives well in salt water but still likes a fresh-water rinse.
An outboard is a drive unit that combines the engine, gearbox and propeller in one housing and hangs from the transom. It is the main power source for small boats and the tender motor on larger yachts; modern production is now almost entirely 4-stroke.
The price of that practicality is that cooling water passes through the engine itself. The table below sets out the key checks.
Outboard motor checks
Check / symptom | What to look for |
|---|---|
Tell-tale jet (pee hole) | Water should be coming out while it is running; if not, the engine can overheat within minutes |
Carburettor | Fuel left standing for months goes stale and forms varnish - the number one cause of trouble |
Transom bracket and lock | A loose clamp can mean the motor ends up on the seabed |
No water from the tell-tale means either a blocked passage (clear it with wire) or a tired impeller; outboard impellers are a yearly service item too. If the boat is laid up for a long time, shut off the fuel and run the carburettor dry.
After each saltwater use, run it on fresh water if possible (with flushing muffs). At the end of the season, the routine for a small motor comes down to impeller, gear oil and spark plugs. Two words for tender owners: lock and safety lanyard.