We've just acquired a 325, Sandack, with sail number 30. Had a look at the propeller shaft with the engine running and it has a lot of vibration movement. The engine is on original Yanmar mounts. They are over 20 years old and due for replacement. The mounts are on wooden wedges on top of fibreglass box section and no sign of any access to nuts inside the box section.
The first attempt to remove a bolt caused it to shear. The other easily accessible bolt turned out to be already sheared. We're guessing that all the bolts are likely to shear when we attempt to undo them. It doesn't look as if we can replace the mounts without removing the engine.

I couldn't find any reference to engine mount problems on the forum. Does anyone have experience of replacing the engine mounts on a 325 and is this a known problem?

All I can offer is that the usual practice in fibreglass boats is to have a strip of steel plate under the glass on the top of the engine beds with threaded holes to take the engine mount bolts.
Sadly, I am sure you are going to have to take the engine out to extract the broken remains of the bolts.

Thanks, that's helpful. We're probably going to drill an inspection hole to confirm what's going on before we shear any more. And we're resigned to engine removal. It's unavoidable.

The inspection holes indicated that the fibreglass box section has a piece of wood glassed inside to the 'ceiling'. It looks as if the wooden wedge above is screwed into it and that the engine mounts are held in by coach bolts screwed into the wedge and into the wood below.

During an engine service some years ago the yard found that two of the Yanmar mounts needed replacing. Their sub-contractor did that by jacking up the engine (Yanmar 2GMs aren't very heavy!) to remove the old mounts and replacing them with generic (ie non-Yanmar and cheaper) mounts. I'll try and find more details, but the company that did the engine service has ceased trading.

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We did take the engine out. We devised a number of approaches to removing the sheared bolts. But, in the end, it seemed simpler to move the engine back a couple of centimetres and drill new holes. We fitted new generic anti-vibration mounts and got everything lined up. Of course, there was the inevitable fettling of access flaps that no longer fitted. Once it was back in its new place, the engine ran up nicely with reduced vibration. Not surpring, given the decrepit state of the old mounts.

As a bonus, we discovered that the exhaust outlet had broken internally and we replaced that as well as getting the injectors serviced and giving the engine a general clean up and repaint. Looking forward to trying it on the water.