Engine mounts

[rustydiver]

They have been on the boat from new so 2003. 

Is there a way of testing them. I Seem to be getting a rattle noise on low revs. 

Are they easy to replace. Being they are old and operating in a hostile environment think it could be time for a change  

 

[Bee]

6 minutes ago, rustydiver said:

Rattle. Could be so many things. If the engine was installed reasonably well there should not be a problem. If the mounts are strained, e.g. bearers are flat but engine is installed at an upward angle or engine is higher on one side / one end or something then the metal parts of the mount may touch and rattle. More likely is that the nuts and bolts need checking for tightness. Grab the engine and give it a good shake, get a bar between the metal parts of the mount, any signs of separation? Careful though, engines are heavy and if it slips off things can get damaged. Even more likely is that something else is rattling. Have you got a Python Drive or decent flexible coupling? If there are no signs of misalignment or wear on anything to do with the shaft I doubt there' s a problem.

 

 

[Tony Brooks]

When the small bolts securing the mount base to the engine bed work loose they do rattle so that would be my first check.

[rustydiver]

Thanks I will give it s good checking next time I'm at the boat.

Won't be for a few weeks though. 

[Stilllearning]

Having checked whether there are any loose nuts on the mounts, it may be worth running the engine, then put it in gear, and rev it a little bit. If the rattle disappears it could be a slightly tired drive plate.

[Taslim]

On 10/12/2017 at 09:55, Stilllearning said:

Having checked whether there are any loose nuts on the mounts, it may be worth running the engine, then put it in gear, and rev it a little bit. If the rattle disappears it could be a slightly tired drive plate.

^^As above^^. If it's a 'rumbly' rattle then possibly mounts otherwise look to drive plate or some heat shield/cowling floating about.

Last time here it was a fan cowl.

[Humblespud]

Our "engine" rattle turned out to be weed hatch bottom plate vibrating on sides of it's chamber. A piece of split hosepipe raised it a few mm and all is now quiet. Not unheard of according to the lovely boatyard that detected it.

 

[ditchcrawler]

Just now, Humblespud said:

Our "engine" rattle turned out to be weed hatch bottom plate vibrating on sides of it's chamber. A piece of split hosepipe raised it a few mm and all is now quiet. Not unheard of according to the lovely boatyard that detected it.

 

We had that on a GT hull, I single piece of pipe between the cover and the bottom plate. a second piece was welded it to act as a stiffener

[larryjc]

I would also suggest a drive plate.  14 years on one is a good time and they do wear out.  How many engine hours do you have?  I had exactly this on a Nanni with a PRM150 box a few years back with about 3000 hours.  Try the long screw driver to the ear test.  Put it on the section between the engine and gearbox and listen.  Its surprising how much you can hear.  I've also had engine mounts go and they tend to be more of a distinct clicking type of rattle rather than a rumble.  One test is to undo the nuts on the gearbox out put flange and remove the bolts holding it to the propshaft flange.  Let the engine settle, the two flanges should be at the same height and parallel to each other.  You can adjust the hieght of each mount to achieve this.  On my current boat there was a horrible loud rattle until the engine came under load. Readjusting them sorted the noise out.