Servicing the Motor

We service Wildwood’s motor every year, and every year I wish I had written down all the various bits I need to do the job. Inevitably we end up missing one vital ingredient, which means another trip in the dinghy, drive in the car to the shop, which will of course have just closed for the weekend, meaning a couple of hour job turns in to a two weekend mission to complete… arraggh!

So this time I have written down a list of everything we need, along with a step by step guide of all things we need to do. Hey it might even come handy to you the next time you are servicing your boat motor!?

If like me you are not very mechanically minded, you can also check out my blog post about Diesel Engine Maintenance. This tells you all about how motors work. Its fascinating! I have been very lucky to have various crew members throughout the years who know lots about motors, so along with doing the diesel engine maintenance course, I now consider myself to be an expert… hmm maybe not. But I can change the oil and impeller and I reckon thats pretty good!

Ok so back to the topic. Here is what you will need to service your motor. The codes below are specific to Wildwood’s motor so you need to replace those with the ones relative to your motor.


  • Diesel
  • Diesel additive stuff
  • Fuel Filter – in line – Z14-15
  • Fuel Filter – in motor – Yanmar 104500-55710
  • Oil Sucker
  • Oil Filter – Z495 or C-1816
  • Engine Oil – 15W-40
  • Impeller – MC97 09-806B-1
  • Oil Filter wrench
  • Socket Set
  • AFS Spanner (adjusts to Any f’n Size)
  • Multigrip Pliers
  • Fan belts
  • Air Filter
  • Anodes
  • Rubbish bags
  • Baby wipes
  • Paper Towels
  • Ice cream container
  • A good looking assistant
  • A couple of hours
  • A few beers


  1. Fill up your fuel tank with diesel and add the diesel bug additive. I’ve had diesel bug before and it is not nice. It is like snotty stuff that grows in diesel tanks and it then blocks your filters and the motor won’t work. And then you have to cut your boat to bits to get the tank out and take it in to someone to steam clean it, and then reinstall it again and well yes it SUCKS! You can prevent it by keeping your tank full and adding the additive.
  2. Run the motor for 10-15 minutes or so to warm up the oil. This makes it heaps easier to suck out with the oil sucker. Most boat motors don’t have the space to allow you to empty the oil from underneath, so your only option is to suck the oil out from the top. This super cool oil sucker has a long tube on one end. You turn off the motor and then insert the tube in the dip stick hole. Pump up the pump and it simply sucks all the oil out and then contains it all in the handy container until you can get it to an oil recycling place. It is clean and easy. LOVE IT


3. While you are waiting for the oil to suck out, you can have a beer and replace the oil filter. You can either buy the genuine branded oil filter, or many oil filters are interchangeable. So instead of buying the more expensive Yanmar oil filter, we get the cheaper Repco (or insert your local car part franchise shop name here) filter instead. They have got a book in their shop that will tell them if the parts are interchangeable. Using an oil filter wrench makes it heaps easier to get off. Put the old filter quickly in to the ice cream container, and mop up any drips with the paper towels.

4. Once the oil has all sucked out, you can put on the new oil filter and add some new oil. Fill the oil filter up with fresh oil before you screw it back on to the motor. Add the fresh oil to the top of the motor. This is easier said than done with the ceiling being very low on our boat motor compartment, but we make do with an old soft drink bottle cut in to a funnel and container.


5. Check the oil level with the dipstick and top up as necessary.

6. Now change your fuel filters. We have one in the line that runs from the fuel tank to the motor, and then another one in the motor. Get your ice cream container handy as otherwise you will get fuel all over you and all over the boat. The inline fuel filter has got an arrow on it showing you which way the fuel should travel through it. Just make sure it is pointing in the right direction and you are good to go. I really want a racor filter. These cool filters have a glass bowl at the bottom that allows you to empty out any water that makes its way in to the fuel. Handy!

7. Once you have replaced the fuel filters, you will need to bleed the fuel through the motor. I am not even going to try and explain how to do this, but if you don’t know how to do it, then you need to learn! My tips – press the little lever down all the way – and it takes longer than you think for the fuel to come through. Also point the fuel screw bit away from your eyes… just a few words of wisdom from someone who has already make the mistakes for you.

8. Next check your air filter. Either clean it or replace if required.

9. Check your fan belts and always have spares on board. We have got one on board that drives the fridge that needs replacing and do you think we can find a replacement the right size? Annoying.

10. We replace the impeller every year as well. These are really annoying if they break as your motor can quickly overheat and all the bits of the impeller can get sucked through the motor. This will inevitably happen when it is really rolly rough conditions when the last thing you feel like doing is grovelling around in the engine compartment. We keep the old ones as back up replacements if they are still in good condition. Take a photo of the impeller before you take it out of the water pump so you know which way to put the new one back in.

11. We also check the anodes in the engine every year. These sacrificial bits of metal get eaten up by the rusty bits before your engine does, so it makes sense to ensure they are still there and doing their job. They are really tough to get off and the skins of many knuckles have been sacrificed in the process of getting them off. We now have a specialised long bar to assist the socket handle.

12. I also clean out the water strainer. This is where the water comes in to flow around the motor and the heat exchanger for the fridge. There are usually little critters and bits of sand and stuff in there. Its worth cleaning it out. Have a towel handy. Water will come in everywhere, so clean it quickly and get it screwed back on ASAP!

13. Finally check the oil level again with the dipstick and run it for a while. Clean up the engine compartment – it makes it heaps easier to see if there are any issues if you know it was clean in the first place. If you come back and it is covered in oil then you know you have got a problem!

Wildwood has a saildrive, and we change the oil in that as well when we are out of the water, we replace the anode and paint on prop-speed to our propeller too. If you have a shaft drive then there is, I believe, some additional maintenance required.

Love your motor and it will love you back. Well that is our theory anyway.

Anything I’ve missed?



16 thoughts on “Servicing the Motor

  1. Very informative – we both did a marine engine course. It was imperative when a storm stirred up all the rubbish in the bottom of the old tank and clogged the filters every ten minutes. We got it down to a filter change and back running in ten minutes, which was good as it stopped at the most inopportune times!

    Liked by 1 person

    • Why is that always the case!? I think I would need more practice to get it down to 10 minutes! When I got the diesel bug it was the worst. Ended up stuck – anchored in a big blow en route to the haul out yard because of that bug. Couldn’t pull the anchor up to sail off. Ended up getting rescued. Not fun…

      Liked by 1 person

  2. A truly spot on blog about annual maintenence of the diesel. I had learned the hard way about the impeller 8 years ago. Like all the issues on your list, you can do them during the day while in the harbor or at 0200 hrs in a tossing sea! Good blog.

    Liked by 1 person

  3. Really good advice, Viki — a good looking assistant and a couple of beers make easy work of engine maintenance. Seriously though, changing out impellers whether you need to or not is something we recommend as well. For the price of one, a person can save themselves a huge headache.

    Liked by 1 person

  4. Viki, as I mobilized this morning to change my oil per your article’s instructions, I came across a very serious omission.

    In Step 3, you wrote, “While you are waiting for the oil to suck out, you can have a beer and replace the oil filter.”

    Now, I do believe most people understand that the specific filter one needs will be determined by the engine one has.

    But, to my great dismay, I see you neglected to provide a specification for the beer. This is without question the most important part of the job, the one without which it does not proceed.

    And so I stand here, hovering indecisively over my oil sucker, anxiously awaiting your reply. . .

    Liked by 1 person

    • Lol! Eeek! How could I have omitted such a crucial point?!
      The answer of course is the coldest one available. Seeing as the damn fridge fan belt is slipping and we can’t find a suitable replacement the fridge isn’t working as well as it should. This means some beers are warmer than others. You must aim to find the coldest beer available to assist with quenching the thirst acquired by performing these critical tasks. In our case it was a Heineken for Andrew and a Corona for me. Hope that helps. Good luck! 😉


  5. Pingback: Spare Parts | Astrolabe Sailing

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