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Engine mounts


DannyC

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Hi all,

 

Someone who did some work on my boat seemed to think the engine sounded loud when running in neutral (he made this comment when inside the boat). He then took a look at the engine and mentioned that the mounts were loose (he checked one of them) and said that he thought the rubber bit had perished and that we may need to get replacement engine mounts. He was not necessarily looking for extra work from us as we were leaving the yard.

 

Now I didn't think the engine seems unusually loud. I have a feeling that what he hears was the rattling that comes from our radiators when the engine is on. Our service (completed in December) showed no problems with the mounts.

 

Anyway, we had someone from a different boat yard come to give us a quote on new mounts. He took a look at one of the mounts (the same one as the other guy) and said it was loose. He just agreed that you need to get all 4 done at once and quoted me about £500 in total. He didn't mentioned perishing of rubber or anything like that.

 

Later that day I got chatting to our neighbour, an older guy who has lived on boats for 25 years and worked for numerous boat yards as an engineer. I mentioned that we got quoted 500 for the new mounts and he seemed shocked. He asked me to turn the engine on so he could hear it and see the prop moving. He said it sounded absolutely fine and that he could see by the movement of the prob that there was no indication of alignment issues.

 

I plan to go and check the mounts myself, but I wanted to ask a couple of questions about the rubber on the engine mounts. 

 

- How doI know if the rubber has perished?

- If it has perished, does this mean getting new mounts fitted is a matter of urgency?

 

 

 

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Does the engine shake at tickover in gear? - often a sign of worn mounts.  Also a black soft "soot" round the mount as the rubber breaks up due to the mounts overheating due to excessive movement.  If you do change the mounts, make sure whoever sets it up knows what they are doing.  It's a bit of a dark art setting the mounts, biggest problem is if you get rocking on the diagonals.  And yes, if one mount needs changing, change them all.

 

You shouldn't be able to move the mounts at all by hand, but you may feel movement using a lever. What engine is it?  Three pot engines need a different type of mount (oil damped).

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To be straight, £500 does not sound completely over the top depending on what engine is fitted. Vetus and Barrus Shite are eye  wateringly expensive , the engine has to be lifted and supported and the poor mechanic has to squeeze his body into some strange shapes to reach some of the lower nuts to remove/ refit.

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5 minutes ago, matty40s said:

To be straight, £500 does not sound completely over the top depending on what engine is fitted. Vetus and Barrus Shite are eye  wateringly expensive , the engine has to be lifted and supported and the poor mechanic has to squeeze his body into some strange shapes to reach some of the lower nuts to remove/ refit.

Yes I thought £500 might not be over the top. By the way, my Barrus isn’t such a bad engine Matty.

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It is a Barrus. The guy said each mount would be £50 plus VAT. When the engine is ticking over it moves moves a bit but not excessively (this is what i think from my limited experience with engines).

 

I'll have a look for the black soot when I get in there and take a look.

Just now, ditchcrawler said:

Is the lose one still lose?

The first guy to look tightened it, but I still think it needs looking at...

 

It has just thrown me because the older guy said the engine sounded and looked fine, but then again he didn't feel the mounts.

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1 hour ago, DannyC said:

It is a Barrus. The guy said each mount would be £50 plus VAT. When the engine is ticking over it moves moves a bit but not excessively (this is what i think from my limited experience with engines).

 

I'll have a look for the black soot when I get in there and take a look.

The first guy to look tightened it, but I still think it needs looking at...

 

It has just thrown me because the older guy said the engine sounded and looked fine, but then again he didn't feel the mounts.

How did he tighten it. If he just ran the top nut down until tight they'll probably be all unequal now.

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3 minutes ago, bizzard said:

The top nut is left alone it will maintain the original height, its the one underneath that you run up and tighten.

Unless it has vibrated down.

1 minute ago, DannyC said:

Unless he just did the bottom one/ or the one that he felt was loose...

 

The weight of the engine is sat on the bottom one so it is the top one that appears loose.

Edited by Alan de Enfield
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I've never known the top nut to ever move, usualy a self locking nut.

10 minutes ago, DannyC said:

so he used one spanner to do it - which makes me think he didn't do it properly.

You would only need one spanner, for the nut undernearth, you don't touch the top one. You only touch the top one's when doing a complete engine re-alignment.

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Ok, so I'm going to go and take a look at the mount that has been supposedly tightened by the first guy. The top one should be tight (possibly self locking) and then I need to check the one below.

 

I presume that if there is a problem they will be loose to the touch. 

 

Am I on the right lines here?

 

Thanks

 

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16 minutes ago, DannyC said:

Ok, so I'm going to go and take a look at the mount that has been supposedly tightened by the first guy. The top one should be tight (possibly self locking) and then I need to check the one below.

 

I presume that if there is a problem they will be loose to the touch. 

 

Am I on the right lines here?

 

Thanks

 

First take a look at the top nut and look at the threaded stud just above it. If he's screwed that nut down you should see a dark mark where it originally was. If so I'd unscrew it to cover that mark,   ''not ideal but better than leaving it''   and then bring the bottom nut up and tighten. And while your about it I'd check the other three bottom nuts are up and tight.  You need tight nuts, like when you've had a fright.

Edited by bizzard
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20 minutes ago, DannyC said:

I presume that if there is a problem they will be loose to the touch. 

Not with the weight of the engine sitting on them. Loose would mean that there is a gap between the engine bracket and the top nut.  If there is a washer below the top nut and you can spin the washer then it is loose.

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So I went and had a look this afteroon. One of the mounts (the one the first guy checked) has a bolt that seems half loose. Well, it is unlike the others.

 

I felt underneath it for the one underneath one and that the one underneath is right there and so is the rubber. It is like they are squished together.

 

 

See the pictures as I am doing a bloody terrible job of explaining myself!

 

The one that is "loose"

 

IMG-20190211-WA0003.jpg.3e20d23b6d90429b7f1b4333e0d91302.jpg

 

The one on the opposite side that wasn't checked by anyone . This one looks different...

IMG-20190211-WA0002.jpg

Edited by DannyC
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19 minutes ago, WotEver said:

I can’t see a mount in that first pic, just a bolt. Am I missing something?

 

Is the bottom nut out of shot below that black metal (engine bracket?) 

Despite what Danny claims I agree with you. The first photo seems to show part of the back of an alternator so scaling from that the part Danny says is part of the mount looks much more to me, size wise, like the actual engine bed. Could this ne a redundant stud & nut? I can't see an engine foot in that photo either.

 

So better photos please

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6 minutes ago, DannyC said:

Yeah the bottom nut is out of shot. It's kinda of sandwiched underneath the engine bracket with the rubber bit. 

Can't be certain with that first pic but it looks like the bottom nut has wound down, I'd try winding it back up and tighten it. Don't touch the top self locking nut. There should be flats or hex for spanner or grips on top of the stud to hold it still whilst winding the nut up.

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