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Home \ Sailing \ Technical \ Changing the Oil on our Yamaha F6CMHS 6hp Outboard

Changing the Oil on our Yamaha F6CMHS 6hp Outboard

Most sources online, including Yamaha, recommend changing the oil on a 4 stroke outboard every 100 hours, unless the outboard is new in which case it will need an oil change after the first 20 hours. We’ll admit that it has been around 2 years since the oil was last changed, and whilst we’re not sure how many hours we have added to it since, we felt it was well overdue.

First, run up the 6hp Yamaha engine for a few minutes to allow the oil to warm up. We use an old fender with the top cut off, suspended from the carry handle and filled with fresh water to ensure the leg is submerged. The exhausted cooling water conveniently keeps the fender full but we always have a hose pipe on standby to top things up.

Next, remove the engine cover. Remove the oil filler cap (dipstick) to break the airlock and using a 10mm socket slowly remove the drain plug. Ensure you have something underneath to catch the oil!

As you can see from the below photo our old oil was dark brown/black in colour. This is normal for old oil but proves that an oil change was necessary.

Once the oil has finished draining replace the drain plug and measure out 0.6l of new oil. We used Quicksilver 4 Stroke 10W-30 Marine Engine Oil, available from many chandleries and online. Slowly refill the engine with the new oil, checking that there are no leaks coming from the drain plug.

Screw the filler cap (dipstick) all the way in, then remove and check the new oil level. Ideally it will be half way between the markers.

Finally give the engine another run and check for any leaks.


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