What symptoms do you get with failed engine mounts?

[chrishelen]

I thought my gearbox was on its way out as everytime i put the engine in gear(Volvo 2001) there was a rattling/grinding noise coming from below,it turned out to be the port side front mount had come loose,
Tightened it up, no noise,Pheeeeew.

[Bosun Higgs]

What's the worst or most likely drama that can happen if all is NOT well?

I repaired a boat in Spain once which had had engine mount failures, the engine had moved off the bearers at sea during a gale and as a result had shorted out the supply cables to the starter motor, set fire to the galley woodwork and all the wiring insulation as well as burning through the tops of three batteries.

That might be an extreme but I did once find on my own boat a stud to an engine mount ( Volvo 2003) which had sheared completely but was invisible until the engine was lifted up with a crowbar.

I'm guessing you have a 1GM. If so the mounts are very soft and also the rubber which is vulcanised to the steel of the mounts does detach over time as the steel rusts. A handy technique to check is to use a crowbar between blocks of wood to gently lift the engine whilst the mounts are still fixed. You will soon see whether the rubber is still attached or has come loose.

The 1gm does vibrate at rest and is not the smoothest on the run either.

[skipper_stu]

In the thread re impeller prices on the Scuttleback forum the subject of the cost of engine mounts arose.

In all my years of boating I have never had cause to consider the mounts.

So how would I know if there was/is a problem?

I changed my rear ones because on the MD22 the sea water pump is mounted on the rear top of the engine, when the impellor is changed the sea water trickles over the mounts and they corrode badly.
The engine usually runs at about 2200 revs to give 6 - 7knots. However when full throttle was used vibration appeared. On inspection, the rust had made the rubbers delaminate from the metal covers, allowing the engine to be pushed upwards "off" the mount under full chat.
Stu

[PetiteFleur]

If you do have to get new mounts and are shocked by the price of Dealer prices, try Trelleborg who took over the Metalastic range from Dunlop years ago. Marketed as 'Metalastic Cushyfloat'. If yours look like the Metalastic ones the chances are they are. They should be marked on the old ones the correct model no. with the rubber hardness.
See:- http://www.trelleborg.com/upload/Ind...%20revised.pdf
MUCH cheaper than the Dealer ones, particularly if you can get them at Trade Price.

[Gypsyjoss]

If you do have to get new mounts and are shocked by the price of Dealer prices, try Trelleborg who took over the Metalastic range from Dunlop years ago. Marketed as 'Metalastic Cushyfloat'. If yours look like the Metalastic ones the chances are they are. They should be marked on the old ones the correct model no. with the rubber hardness.
See:- http://www.trelleborg.com/upload/Ind...%20revised.pdf
MUCH cheaper than the Dealer ones, particularly if you can get them at Trade Price.

Agent for Trelleborg is Robush Vibration Solutions www.robush.co.uk
I recently bought 4 new RAB2 mounts for my Buch DV24 for the princely sum of £72.02 (inc. postage) from this company.

[skipper_stu]

Thats what I said on the other post
Stu

[ITH]

In the thread re impeller prices on the Scuttleback forum the subject of the cost of engine mounts arose.

In all my years of boating I have never had cause to consider the mounts.

So how would I know if there was/is a problem?

Last October I had to replace the port side (fwd) engine mount on my Volvo Penta 2003T. The mount itself had broken through, just below the mounting bolt hole, but it only came to light when I was installing a new electronic clutch/throttle system.

The two broken pieces of the mount ended up about 5mm apart, a vertical movement which must have put the engine alignment out of kilter. With hindsight I should have pursued the occasional 'knocking' noise coming from the engine bay (generally at engine start-up) with more vigour. And on the same basis I guess it could explain the very small, but unstoppable, drip from the shaft seal.

Tracing it back, I reckon the mount cracked when I picked up a stray mooring line which wrapped round the prop and stopped the engine with something of a clunk.

The new mount (a VP replacement part) is a much beefier affair than the old one, which is now listed as obsolete on the VP parts list