Yanmar SB12:  Engine Removal
This page was last updated on 2 August 2001.

It was only just over a year ago, in late May and early June 2000, that I worked diligently to install the Yanmar SB 12 that proved to be such a disappointment.  (Forget how I did that?  Click here to go back in time.)  It seemed strange to be about to undertake the removal of the engine, and to replace it with a brand new one.

The last thing I really wanted to do was haul my boat during the prime of the season, but the handwriting was on the wall--it was time to do the repower.  With the new engine sitting in my garage, I just had to make a call to schedule the boatyard for what I hoped would be a quick haulout.  Although I wasn't sure, I figured I should be able to do the repower over a five day period.

MONDAY 7/31/01

I motored Glissando from her mooring into the nearby boatyard for the scheduled haulout--the last time I would be running the old engine.  True to form, the SB 12 smoked up a storm.  The day had dawned foggy on the coast, and I joked with the Travellift operator that my engine was actually the cause of the fog.  Within minutes, my pride and joy was plucked unceremoniously from the water and deposited on the hard--right next to a lovely, ripe-smelling dumpster.  Thanks, guys--I guess they didn't want me to hang around the yard too long!

The first order of business, once the boat was blocked, was to eliminate my one and only item on my "rely on others" list.  Buttonholing the service manager, we went to find the yard's prop puller--a piece of equipment that, tragically, I do not own.  The new engine requires a new propeller with different pitch.  I had to remove the prop before doing anything else because it has to be done before breaking loose the coupling inside--the puller requires that the shaft be stationary.  A few minutes later the prop clanged off; I returned the puller, and then began my week of self-sufficiency.

First, I spent some time preparing the boat for the traumatic event ahead.  Using a large piece of corrugated cardboard, I created a sort of custom protective pad inside the cabin, covering the sole and even turning the cardboard up the sides of the settees and covering the port berth as well.  Then, I spread a number of drop cloths everywhere, inside and out.  I moved the settee cushions and most of the stuff from the cockpit lockers up to the vee berth, and spread out my tools in the cabin for easy access.  Now I was ready to really get into it!

I began by disconnecting the batteries, and then the alternator and starter connections on the old engine.  I labeled these wires for future reference and taped them to the side of the engine room to keep them out of the way.  Next, I disconnected the raw water intake hose, the exhaust hose--it was lined with nasty black carbon from the obviously excellent and efficient operation of the engine--and the fuel line.  I removed the old control cables and the engine shut-down cable, and then disconnected the shaft coupling from the Drivesaver on the engine.  Then, I removed the bolts securing the engine to the mounts, and, to make removal easier, cranked up the bottom adjusting nuts to raise the engine mount flanges to nearly the top of the studs.  This is helpful since the engine is set back from the companionway, and the chain hoist must sort of pull the engine forward first, as well as up--pulling it over the exposed studs can be difficult.  The after two mounts were hard to reach with the big wrench, so eventually I gave up trying to raise those too much.  I also removed the raw water strainer from beneath the engine to give the thing a little more clearance coming out.

Next, I rigged up my trusty chain hoist from the boom above the companionway.  I moved the main halyard to the center of the boom, and protected the sailcover with a rag wrapped round.  I hung the chain hoist from a thick line that I tied around the boom, and hooked it to the engine.  Now I slowly started taking tension, to see how the engine would move.  Soon, I noticed that the boom was being pulled down, and the engine was not really moving--it was stuck on those after engine mount studs.  I ended up removing the lags that hold the mounts to the engine foundation, which was possible with a little  contorting and creative wrench use--the clearance is tight around the engine flanges.  Soon, though, the lags were out, and I hoisted the sb12cockpit2.JPG (150807 bytes)engine up, up and away, setting it--with some effort--onto the bridgedeck in the cockpit, which was protected with rags and a piece of plywood.  Then, moving the chain hoist slightly aft on the boom, I moved the engine to the safety of the cockpit well.

I had originally thought I'd hire the yard's crane to lift the old engine down from, and the new engine up to the cockpit.  Soon, though, I started thinking that there was no reason I couldn't use the boom to swing the engine out over the side of the boat, and lower it into my waiting truck below.  By the end of the afternoon, I had decided to proceed in this manner, and I soon had the engine hooked to the hoist again, the boom swung out, and I lowered the engine onto the crude wooden platform that I had saved from when the engine was shipped to me.  Nothing to it!

This left behind a relatively empty engine bay. I spent some time cleaning things up--it wasn't too dirty, but I degreased everything and cleaned up beneath the Waterlock in the bilge.  I removed the wiring harness from the old instrument panel, which I am replacing, and cleaned out anything else that was unnecessary.  I removed the old engine mounts, and then pulled the shaft and coupling out from the inside--I am reusing the coupling, so there was no need to remove it But first, I temporarily placed my new engine template on the beds and, using the shaft coupling, marked where the mounts would go.  I moved the marks forward an inch to account for the Drivesaver coupling.  These marks will be critical for the placement of the new engine, as it must be able to mate with the existing shaft.  I also removed the stuffing box so that I'd have a clear view of the stern tube for running my alignment string..

By my calculations, the only modification to the engine beds that will be necessary will be to add slightly to their height.  That's where the slick engine alignment template comes into play.  But it was the end of the day, and modifying the beds will be tomorrow's project.

Click here to continue.


Glissando, Pearson  Triton #381

We recommend viewing this site with your screen resolution set to 1024 x 768 or larger.  Problems?  Email the webmaster.

1999-2014 by Timothy C. Lackey.  All rights reserved.  No duplication of any portion of this website allowed without express permission.  Permission may be obtained by emailing the webmaster.