Changing Oil In 4 Stroke Outboard Motor

Changing oil in 4 stroke outboard motor – Model: 2.2hp 4 stroke engine

Changing oil in 4 stroke outboard motor..3 hp outboard motor for sale in Australia

You need:

A 12 mm ring and open end spanner
A rag
A small funnel
A small measuring jug (Funnels and measuring jugs are cheap in supermarkets)
Engine oil – 300 mls of light good quality engine oil with no additives. Change after 10 hours running or at least annually.
Note: The handbook says use 320mls of engine oil but this seems to overfill the crankcase. Check the oil level with the dipstick – 300 mils should be enough.

You might even start by putting less than 300mls of engine oil – sometimes there is a residue of oil in the crankcase before you start. Use the dipstick to check the oil level before adding more oil.
May need – fine emery paper
A tray to catch the used oil. Can be a plastic container of some sort.

Changing oil in 4 stroke outboard motor is not difficult – just get organised before you start and do it somewhere it won’t matter too much if you accidently spill oil.

There are two ways of emptying the used oil from the engine: The correct way and the easy way.

1: The hard way. With the outboard in a horizontal position – Undo the drain plug located under and behind the fuel tank.

3 hp 4 stroke outboard motor for sale in New Zealand and Australia

It takes a 12mm metric spanner to undo the oil drain plug.  If you have “ring and open end” spanner you are best to use the ring end to break the initial seal as the plug is likely to be tight. Once the plug is loose there is not room enough to use the ring end but use it again for the final tighten when replacing the plug.

Under the head of the bolt used as the oil drain plug there is a soft alloy washer. Do not over tighten the plug as you may damage this washer or, worse, strip the thread out of the bolt hole. Lubricate the thread on the drain plug bolt before replacing it – just smear a little oil on the thread.

(Note: If the flats on the alloy washer are damaged or have a burr on them it may leave a tiny gap that hot oil may seep out. If necessary give the surface of the alloy washer a very light rub on fine emery paper to smooth it. Go easy here as you don’t want to wear the alloy away.)

Take care. It is best to drain the oil when it is hot after the engine has been used.

Pick the outboard up and hold it drain hole down over a tray to catch the used oil. Clean up any mess with a rag. Do this job somewhere you won’t ruin a clean concrete floor if you spill oil.
2: The easy way. Undo the oil filler plug beside the top of the motor and hold the outboard motor upside down over a tray and let the oil pour out. Make sure the petrol cap is tight. Continue draining the oil until all the oil has trickled out.

Replacing the oil:

Changing Oil In 4 Stroke Outboard Motor

With the outboard mounted upright on the transom (or some other bracket) use the funnel and the measuring jug to slowly pour about 300 mls of oil into the filler hole. Check the oil level after the oil has had a minute or two to settle down. If there is a residue of oil in the motor you may not need to put the full 320 mils in. After a brief run of the engine, check the oil level again – but first allow time for the oil to settle in the crankcase before checking it.


• Don’t use the red funnel supplied with the outboard. It has a filter mesh and is for petrol. Oil is too thick to flow through the mesh.

• If you tip the outboard back and oil oozes out of the carburetor or the exhaust – you have too much oil in the crankcase. Put the outboard upright, let the oil settle for a few minutes and check the oil level. If necessary tip a little oil out. Note that the engine will smoke like a bush fire if there is surplus oil in the carburetor, cylinder or exhaust but this will stop once all the stray oil is burnt.

• Stowing the outboard. The motor can be transported on its back – petrol tank down. These are four stroke engines and the oil in the crankcase can seep out if the carburetor or exhaust is lower than the crankcase. It’s best to keep a rag under any horizontal motor.

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