Any tips on replacing an engine mounting

[rlea]

Hello.
The rear starboard mounting on my 3 cylinder perkins is shot.
Before I have a go at replacing it, I thought I'd post a thread to see if:
a, I've got the job planned ok and

b, Someone may be able to pass on advice to make the job a little easier?
The plan is to take the old mounting off in my local marina on the water. The engine sits too far back to put a sling around and take the pressure off so I'm hoping to jack the rear end up, failing that, there is enough thread to screw the old mounting down a cm or so, then chock the rear end and let the engine down.
I'm not planning on taking the prop off as there should be enough play in it to leave well alone. That's it, apart from shearing the heads of bolts and not being able to find a replacement part, I can't see any problems.
What do you think!

 

[vyv_cox]

I have not done the job on this engine but in general you will almost certainly have to disconnect the prop shaft coupling from the gearbox. Unless you do this the height you can gain by jacking the gearbox is the clearance between the shaft and the stern tube, i.e. 1/4 inch max. Once the shaft is uncoupled you can lift the gearbox as much as you need.

Changing one mounting is not recommended as the others will have set a certain amount. Better to replace both aft ones.

 

[boatmike]

Personally I would disconnect the propshaft (easy enough) and jack up the rear completely. It is unusual for one engine mount to fail without the other being a bit tired as well so I think it's false economy to replace just one side. To avoid vibration they both need to be of equal resiliance. If the front ones are not too bad you can just replace the rear ones rather than all four but I would not be inclined to replace just one....

 

[nickd]

When my straboard rear mount went, the one diagonally opposite was also wrecked
I would replace all of them

 

[NickRobinson]

Hi
I've done two engines without disconnecting the shaft, one mount at a time of course.

The access can be interesting- the mounts usually have female threads (sockets) with either bolts or riser studs fitted.
It may be possible to grind these off if they won't unscrew then the amount you need to jack up will be zero/minimal. If risers with adjustable lock nuts come off, don't change the position and replace at the same height. (the book says you should feeler gauge the shaft coupling afterwards but I have had ok results tested over years)

These people are really good- the staff you speak to know their stuff and if you were able to visit they'll 'take you through the back' to select. One quarter the price of Yanmar too- (no connection etc..)

http://www.avindustrialproducts.co.uk/ and their ebay ad, http://www.ebay.co.uk/itm/Flexible-...tEquipment_Accessories_SM&hash=item232b3195d1


Nick

 

[rlea]

Thanks Vyv.

I have not done the job on this engine but in general you will almost certainly have to disconnect the prop shaft coupling from the gearbox. Unless you do this the height you can gain by jacking the gearbox is the clearance between the shaft and the stern tube, i.e. 1/4 inch max. Once the shaft is uncoupled you can lift the gearbox as much as you need.

Changing one mounting is not recommended as the others will have set a certain amount. Better to replace both aft ones.

Found your talk at the Venturers really interesting the other month too.

 

[rlea]

Thanks Mike, will replace both.

 

[Lakesailor]

Excellent. A perfect Full Lakesailor.

 

[rlea]

Hi
I've done two engines without disconnecting the shaft, one mount at a time of course.

The access can be interesting- the mounts usually have female threads (sockets) with either bolts or riser studs fitted.
It may be possible to grind these off if they won't unscrew then the amount you need to jack up will be zero/minimal. If risers with adjustable lock nuts come off, don't change the position and replace at the same height. (the book says you should feeler gauge the shaft coupling afterwards but I have had ok results tested over years)

These people are really good- the staff you speak to know their stuff and if you were able to visit they'll 'take you through the back' to select. One quarter the price of Yanmar too- (no connection etc..)

http://www.avindustrialproducts.co.uk/ and their ebay ad, http://www.ebay.co.uk/itm/Flexible-...tEquipment_Accessories_SM&hash=item232b3195d1


Nick

Thanks Nick. I've not seen the ebay one before. I'll just see if I can send you a photo of one of the mounts.

 

[rlea]

Cheers Mike.
If I go with disconnecting the prop, I take that it's ok do so on the water and what about realignment of the prop once the new shocks are in place?

 

[MASH]

The mount in that photo looks to me as if it would slide out sideways if the engine was supported and the lower height-adjusting nut backed off.

 

[vyv_cox]

Excellent. A perfect Full Lakesailor.

How is that then? Boatmike and I gave the same advice at almost exactly the same time. The OP thanked us both.

 

[mikecontessa26]

The mount in that photo looks to me as if it would slide out sideways if the engine was supported and the lower height-adjusting nut backed off.

agree, looks like they could be done one at a time, the slotted hole should allow you to tilt it and get it out and the new one in

 

[mikecontessa26]

I have to do the exact same job, bought new mounts but a bit dubious about disconnecting my prop and re-aligning it, might ask a mechanic