Yanmar 2GM Post-rebuild Run-up

Hi there,

I recently completed rebuilding this Yanmar 2GM for our Sun 838 sloop. I noticed a lack of information online (or anywhere) about the 2GM (lots about the 2GM20, not the same), so I thought I would post this video in the event other people are dealing with the same engine. Just in time for Spring!

The boat had an old Bukh single-cylinder diesel in it, and when enough salt water had passed through the engine over it's life to completely rot away everything that would make a rebuild reasonable, we bought this little engine for a rebuild and transplant. Since we're not swimming in money, we found this Yanmar for $1000, reported with excess crankcase pressure - high enough to blow the camshaft seal a few times (and likely the owner's patience), as it seems the mechanic improperly diagnosed problem. Anyway, we picked it up, diagnosed the issue as blown rings, stripped it down and discovered the #1 piston was cracked along the ring flanges, the rings were shot and the rod bearings were in rough shape. The engine was reported to have 4000+ hours on it prior to a valve job and Hobbs reset, which now has 1200 hours on it, so I'm guessing the engine has +/- 5200 hours total (wow!!!). However, all the bolts looked brand new, so thanks to Yanmar for using high-quality hardware and making great engines.

The rebuild entailed: new pistons, rings, crankshaft and rod bearings, honed cylinder sleeves (yes, the 2GM has sleeves), rebuilt water pump (didn't buy a new one, just rebuilt it with new bearings and seals), port and polished head, new valve spring retainers, planed exhaust manifold flange, new instrument panel, new Faria hour meter, new (fabricated) exhaust manifold, rebuilt alternator and starter, new water lines, filters, fuel and oil line crush washers and a beautiful new Yanmar grey paint job.

It runs great with 8 hours on it total at 1600rpm with no leaks and no problems. I will also install a separate fresh water/antifreeze intake system on the boat so we can flush the salt water out before shutting it down, which will help in rust/calcium buildup prevention.

All said and done, we spent $1000 on the engine and $1500 rebuilding it. The guy we bought it from had a new engine purchased and installed to the tune of $17,000. With no need in mentioning the fact I don't have $17,000, it's a lot of fun reviving these engines, and if it ever gives us trouble on the water, I now know it inside and out, so I highly recommend doing your own maintenance if you plan to go into remote places (as I like to say, it's not the sailing that keeps you afloat, it's your onboard systems). I feel confident we can get another 3000+ hours out of this little thing.

If you have any questions feel free to ask. I also have lots of photos of the rebuild progress, so if you would like to see something in particular, I probably have a photo of it.

Furthermore, if you have an old diesel engine (marine, industrial, highway) that you would like to get rid of, or rebuilt, please send a message - I'm always interested in reviving the broken, old, beaten and tired..... just not the overly rusty ;)

Thanks to Precision Valve and Crank for excellent machining of the head and great service, Burrard Metalworks for a beautiful instrument panel and Stem to Stern Marine Parts and Service for quick and helpful parts requests.

Cheers,

Quinn Harper
North Vancouver, BC