10 Lessons/Tips from our YSM12 Rebuild

Yanmar Parenting 101

Our Yanmar is a diesel engine, the YSM12 (nicknamed "Yannie" lovingly by Trev). It is 39 years old. It's a simple, robust little engine - consisting of only a single horizontal cylinder. It's Trevor's baby. He's always fixing/cleaning/improving something on it. 

From what I have observed, there are a few key things you need to know to own Yannie:

• Feed it oil often - old engine houses small Troll who subsists on oil. 
• Sometimes even just cleaning parts will help with engine performance. 
• While your girlfriend is away in Miami for work, you should decide to completely remove it from the boat because you've "had enough" of the aforementioned troll.​

The month leading up to this engine eviction was a long saga of trying to figure out why we were eating $7.00 of oil a day. It was a problem that couldn't continue. We tightened things, added gasket sweller, and talked nicely to the troll. All to no avail. 

While we were focused on solving the oil problem, we developed a secondary issue - there was an exhaust leak. Since our engine exhaust is a combination of the burnt oil/fuel mixture and the cooling water - this created quite the mess... 

In the end, although I was shocked to find an engine in my kitchen when I got back, I quickly realized it was necessary. Aside from the fact that it's nearly impossible to work on the engine in the boat unless you are a tiny human - the cylinder head will not actually come off it's studs in there (see top right photo above... the lefthand wall is in the way). 

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Now that you've got some background... I present to you:

10 Lessons/Tips from our YSM12 Rebuild

1. Location, Location, Location
Positioning yourself is key if you're going to remove your engine and complete a DIY rebuild on a budget. We'll admit that this came down to dumb luck in our case, but we ended up at Duck Creek Marina near New Bern, North Carolina. This was the best thing that could have happened to us. The yard itself has all the tools & resources we needed. More importantly, the people at Duck Creek are extremely helpful and generous. As a bonus, they didn't laugh at us when we said things like "this should only take a few days"​... 

2. Don't hurt yourself. 
We did try to remove the engine ourselves, but quickly realized one of us was going to get hurt - although it is​ a small engine, our sketchy plywood-and-mainsheet lift system we crafted was destined to fail.

3. Call around for parts. 
Getting Yanmar parts is sometimes difficult if you don't want to wait weeks to have parts ordered in. We found the best way is to call around before you order anything to figure out the quickest way to get things. In Toronto, you can typically find parts at Eastmar Marine on Gerrard Street (we were lucky they had a gasket set and Trev's brother generously picked it up and mailed it down to us). We also found a luck with J-Way Enterprises for new valves.

​4. Unforeseen delays will occur. 
​Little things will always get in the way. For example: the "full gasket set" that you have mailed down from Eastmar will come with just about every gasket except the cylinder head gasket (the main one you intend to replace). Or, you'll wait all day for the mail at the marina, and finally realize that it said it was delivered in the morning. This will be confusing, but it will turn out that the house next to the marina has the same address and often mail gets delivered there (so you'll have to sneak into someones yard and rob their mailbox). 

​5. Seize the opportunity to clean!!!
Although a clean engine room isn't mission-critical, it's nice to have! We took advantage and got right up in there:

We also had to take the dodger off to get the engine in/out so we got everything off the deck and gave it the most thorough scrub we ever have!

6. Take some breaks to explore.
Especially if, like us, you're on vacation! Duck Creek is a beautiful place - and we still had one working engine! 

7. Know your limits.
Although we're fairly confident in our small engine abilities (between Trev's diesel engine courses/marine tickets & my airplane engine knowledge) - there were a few things we recognized we shouldn't do ourselves. The first thing was removing the injector pump. Once that comes off, you need special tools to re-time it (so we just didn't touch it). The second was the valves, which needed replacing. We purchased new valves and brought them & the cylinder head to a local mechanic to have them seated & hot tanked. 

8. Take your time when reassembling!

The YSM service manual (thankfully) is easily found online. We learned quickly to slow down and follow it, especially at the end when putting everything back together. You save yourself a lot of extra work if you just do things in the recommended order. 

​9. Red oil caps are fast. 
If you paint your oil cap bright red you will go faster. 

10. Be very grateful when it's all said and done!
Not only are we grateful that the engine is back in and working - but also for the people at Duck Creek - thanks again you guys! (Chris, we hope you're reading!). 

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