Anyone have tips for replacing engine mounts on a Yanmar 3HM? In terms of
the logistics, like how to prop up the engine, get the old mounts out, etc.

I have the transmission out now for a rebuild (fwd clutch failed) so it's
the perfect time to replace mounts. I'm just going to do the forward two
(back end of v-drive engine) because those are the two the mechanical
inspection (purchase survey at the start of this year) said were
delaminating. Plus Gallery Marine in Seattle has two in stock, not four. If
this goes easily maybe I'll consider replacing the aft two.

I'm going to go with the OEM mounts instead of PYI since several online
reviews said Yanmar OEMs were significantly better (and they look it too -
a lot more rubber for vibration dampening). The engine vibrates a fair
amount now, and a slight misalignment might be what caused the transmission
premature wear.


Copying a mail from Martin below in 2013 on the list. Martin, I'd be
interested in hearing more if you still recall the work you did (even
though your engine is a Perkins, so the mounts are different). What did you
mean by the existing engine mount bolts didn't meet your standards? I'm
ignorant of what the issue with lag and stripped threaded bolts is. I'm
expecting the existing mounts may be hard to get out because the bolts/nuts
look a bit rusted on.

I saw your suggestion of a scissor jack, but I'm not sure where I would
place that? The engine doesn't have super good flat surfaces between it and
the hull. And the plates the mounts attach to look too small to fit a jack
in. I've read that the mount nuts can just be used to raise the engine
until its raised enough to slip the mounts out (block it with scrap wood at
that point). Is that actually the best way? I have some pictures I could
upload.

Thanks! Hoping to do this project in the next two weeks, which is how long
it will take Harbor Marine to get to the transmission. I thought boats knew
not to break in the summer months, but I guess not!

-Patrick
S/V Violet Hour, LF38
Seattle, WA, now in Elliott Bay marina

------------------------------------
*Martin DeYoung* mdeyoung at deyoungmfg.com
<cnc-list%40cnc-list.com?Subject=Re%3A%20Stus-List%20Yanmar%20Engine%20Mounts%20-%20aftermarket%20replacements%3F&In-Reply-To=%3C23EAE197CC1B594FA8793397EBCD357D7B48ED%40DMI3.DMI.local%3E>
*Wed May 22 13:38:22 EDT 2013*

I replaced all 4 of Calypso's engine mounts (Perkins 4-108) a while
back.  I used the R&D Engine Mounts offered by PYI, Inc.  As none of
the existing engine mount bolts met my standards ( a combo of lag and
stripped threaded bolts) the job became slightly more complex than
imagined at the start.

In 1970 Bruckmann's was laminating a steel plate on top of a wood base
to build up the engine support frames.  Once I understood what was
under all the fiberglass and paint I decided to drill and tap new bolt
holes, using the older ones if possible.

The results when finished were worth the effort.  I did re-align the
engine/reduction gear to the prop shaft.  The engine vibration
transmitted through the hull was significantly reduced with the added
benefit of being confident that the engine would stay put if the boat
broached or was knocked down in a heavy sea.

One of the least expensive tools to purchase that may help is a small
scissor jack to be used in holding the engine in place while changing
the mounts. Let me know if you want more info on how I approached the
process, but there is much already written about the topic available.

Martin
Calypso
1970 C&C 43
Seattle
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