Yanmar might make a great engine but they certainly don’t make it easy to change the oil! The oil filter is inaccessible and placed horizontally on the engine block. If that wasn’t bad enough, the don’t even give you a sump drain nut anymore. This is progress for you!
After the first time I changed the oil on my 3YM20 I vowed to find a better and less messy way to do it.
To get the old oil out of the engine you must use the dip stick shaft. Many companies make oil pumps with a small tube that can be fed down the shaft but their diameter is tiny and even with hot oil, the process is slow, messy and inefficient. So here’s a trick I learned from a mechanic, for which I will always be grateful. It’s obvious really, but don’t try and stick a pipe down the shaft but rather use the shaft as a tube but simply putting a larger diameter pipe OVER the dip stick shaft! I know, I told you it was obvious. However before you can do this you’ll have to cover the small and practically invisible hole at the top of the shaft or it won’t suck.
This helps enormously but if you really want to make it easy then you need to remove the banjo bolt that holds the dip stick shaft in place and have it drilled and tapped to take a brass fitting. To this you can then attach a pump which can be attached in a convenient place on the motor. Of course most other marine engine manufacturers offer this as standard. I cannot imagine why Yanmar do not.
This pic shows the remote oil filter placed conveniently under the front of the engine and the oil sump pump top left.
That covers getting oil out of the engine but what about the filter? It is possible to buy a remote filter kit which allows you to not only place the filter somewhere more convenient but it also allows you to place the filter vertically so oil doesn’t pour out when you unscrew it. Kits are available from ASAP Supplies who are a very knowledgeable (UK) company and prices start at about 100€ depending on what length of pipes you choose.
If you don’t want to go to the hassle of fitting a remote filter, there is a trick to stop you spilling quite so much oil when you unscrew the filter. Normally, we are told, one should run the engine to warm and thin the oil before changing, this makes it much easier to remove. However if you do this, the oil filter will be full , so when you unscrew it, you will spill a lot of oil all over the engine and make a terrible mess. The Yanmar filter is fitted absolutely flush to the block so there’s nothing you can do to stop this. The trick is to run the engine to warm the oil but then wait an hour. The oil will still be runny but the filter will have drained the majority of it’s contents back into the sump so that only a bit of oil will spill out. It’s also much easier to remove a filter that isn’t scolding hot!
I hope that these few simple ideas will make changing the oil on you marine engine, if not a pleasure, at least not such a chore.
Spot the oil filter!