This page was last updated on 26
NOTE: On this page,
you've actually gone back in time a bit. I built this engine template
prior to hauling the boat and removing the old engine, since this was
preparatory work I could do before committing to the project. But for the
sake of chronological continuity, it makes more sense for this page to be at
this order in the sequence of work involved in replacing the engine.
Once again, I found myself building an engine alignment
template. Who knew that I'd be doing this again so soon? It was only
a little over a year ago that I built my first template
for the Yanmar SB12 engine that I initially installed in the boat.
The first step, which I took care of before even ordering the
new engine, was to find out how much, if any, I would have to modify my engine
foundation. I was a little worried that it would be necessary to cut the
foundation down. However, when I started comparing dimensions, I figured
out that, if anything, I might only have to raise the beds a little less
than a half inch. Raising is easy, since I only have to add an oak shim or
something. Obviously, the shaft and the shaft angle are constant, no
matter what engine there is, so the only real changes have to do with the height
of the coupling relative to the engine beds. This is good news.
Once the new engine arrived, I was ready to get to work.
I built the template before the boat was even hauled, as it was an easy thing to
get out of the way, and the template will be one of the first things I need once
the old engine is removed.
here to view a dimensional drawing of the Yanmar 2GM20F. It gives all
the important dimensions necessary to construct a template like mine.
Using the supplied dimensional drawing, I constructed a simple
plywood platform, carefully laid out to represent the basic dimensions of the
engine. The most critical part of building the template is to exactly
locate a surface to represent the transmission coupling, and to properly and
accurately locate the four engine mounting holes, which was easy enough using