replacing engine mounts

[john]

can i replace these with the engine still in situ, one at a time? If so, how do I go about it?. Do I need to replace all the mounts at the same time, or can I just do the two worn ones at the rear. many thanks

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[Guest]

You could try ... but would consider that the engine will sit differently .... I know when I did mine, it meant removing and replacing the mount beams as well ! The old mounts were smaller and no longer available ..... The engine wouldn't line up without changing the beams.

If you are still able to get the same mounts .... maybe. Its worth a try - as all that happens is that you end up doing it the full engine out way !! if it don't work.


<hr width=100% size=1>Nigel ...
Bilge Keelers get up further ! I only came - cos they said there was FREE Guinness !

 

[oldsaltoz]

G'day John,

By your comment "can I just do the two worn ones at the rear" I assume this is a shaft drive set up.

If so, I suspect you need to undo the coupling first, then support the engine on a jack with suitable packing so you don't put the jack through the hull: you can then lift the rear of the engine and replace both rear mounts, leaving the front two to hold it level. Then you have to re-align the coupling/shaft.

Hope this helps

Andavagoodweekend. Old Salt Oz /forums/images/icons/cool.gif

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[Guest]

I had my engine mounts professionally replaced last year -Yanmar 2GM 20- and they did not lift the engine out.In discussions with my surveyor he said to expose the prop shaft so that it can be seen disappearing into the shaft tunnel and then disconnect it from the engine.Use amall wooden wedges to get the shaft central in the tunnel then replace the mounts.Then adjust the engine on the mounts so that it mates with the shaft.Check the gap between the engine/shaft coupling with feeler gauges to make sure it is equal at the top,bottom and sides and you are in business.With this method you have to be laid up ashore or you will sink!It sounded simple but I bottled out and let the yard do it.I seem to recall that it was best practice to replace all 4 mounts so as to get maximum engine equilibrium or something but as they were all well past their sell by date they all had to be done anyway.

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[paulrossall]

How did you know the mounts wanted replacing? I have a Yanmar 2GM20 and I am slightly concerned about the amount of movement at my cutless bearing and wonder if it caused by the engine mounts being worn and allowing the engine to vibrate too much. Mounts have been in 9 years and engine has done 1000 hours. I am about to check the engine alignment first. I have a standard plastic type coupling between engine and propshaft, not one of the very flexible one, what sort of coupling do you have? Prop shaft then goes through a conventional stuffing box and I wonder whether I should have a more flexible arrangement here.
Regards. Paul

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[Guest]

The engineer who checked my engine over shortly after I bought the boat told me they did as they were about 18 years old and very rusty - even I could see this.If yours are 9 years old and have had normal use then I would suggest that they will probably need replacing.I think you will find that the Yanmar Manual recommends replacing the mounts every 2 years!My engine has a metal coupling. I f you are getting excessive cutlass bearing wear then you might wish to consider having the prop shaft inspected where it sits in the cutlass bearing.I had the same problem and when the shaft was looked at it was worn.I then had to have a new prop shaft made.The propeller had gone pink so I had to have a new prop as well!

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[Guest]

Run up to my repairs ...

My engine mounts actually parted in the rear set ...... not possible to see until they were 'cut-away'. The hard rubber section had separated from the metal plates ! They were basically Petter mounts style ....

The engine was moving up to 2 in side to side when working and this caused the coupling and stern gland mount to wear out. I had to run the engine more than I wanted to get her to repairs etc. The shaft moving side to side with the engine basically caused the packing and gland to fail, the shaft ended up with a groove.

The guy who originally fitted the engine built the engine box around the lump .... meaning that it had to be cut carefully to lift out in sections ready to be screwed back together etc. after repairs. The engine bearers were hard wood beams and the engine bolts were driven UP through the beams, meaning that the bolts could not be withdrawn without removing the beams. Of course after near on 30 years that proved a mess !!!

So finally we had the following list of work to do :

Cut away the engine bearers
Remove engine box
Coupling was seized - that was cut off
Lift out engine and g/box as one
Remove stuffing box bulkhead and reglass in
Renew bearers with primed / painted steel angle iron
Brace bearer mounting bulkheads
Brace up stuffing box bulkhead
New shaft
New coupling
New mounts .... Vetus
Refit engine and re-align
New packing and set-up
Clean up all timber edges of engine box and refit with screwed removable panels
Run-up and adjust

Total work has now put my engine back in place for probably the rest of boats life !!!! about 3500 quids worth of work .... but believe me - its been worth every penny with the knowledge that it now will take as much punishment and thrash as I can throw at it !!!!

It is a once only job as far as I'm concerned, but I know that I can sell on / use it / whatever secure in knowing it will do its job.

But note that it all started as a 'renew' mounts job ..... !!!!



<hr width=100% size=1>Nigel ...
Bilge Keelers get up further ! I only came - cos they said there was FREE Guinness !

 

[roger]

I suggest you do some careful checking to find out what mounts are suitable. Vetus for example have a large variety of mount types - and then theres the possibility of moving to Halyard typesoft mounts and a flexible coupling.

<hr width=100% size=1>Roger

 

[vyv_cox]

It will always depend upon the specific installation but it is perfectly possible to replace mountings one or two at a time. Support the engine weight with some sort of tackle, a plank across the companionway is often convenient. Make sure that nothing connected to the engine will be damaged, for example exhaust pipe, gear cables, fuel lines, etc. As others have said, it may well be necessary to realign after replacing engine mountings as the old ones will have set to some extent.

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