Mercury 15/20 EFI Upper Engine Mount

[Steve509926]

Some of you will already know about the "failure" of the upper engine mounts on my Mercury 15hp EFI whilst I was on the "Scotland SIB Outing 2021"
The OB is approx 13 months old and run approx 70 hours.

I took the OB in to have it fixed, hopefully, under warranty.

I spoke to the service tech this morning and he told me the following.

Started OB in a tank, increased the throttle to asses how much vibration/wobble there is. Shut it down straight away as he thought it was dangerous!

Took off the casing to check the engine mounts which appeared to be a little soft, but otherwise OK.

Checked through other possible causes for so much vibration. Everything checked out OK.

Contacted Mercury - Apparently a service bulletin has been issued basically stating that if a customer complains of excessive "wobble" that the engine mounts need to be changed.
Again "apparently" the engine mounts 2019/2020 are made of a softer compound so as to absorb more vibration. The new mounts will be a stiffer compound.

He couldn't explain why for the first 60 or so hours it was running OK for it to suddenly fail for no obvious reason, other than maybe it was because we were pushing the OB hard and running it longer than usual that day.

Obviously the costs are covered under warranty.

I'd be interested to know if anyone else has experienced the same problem.

Once I get the OB back and have run it a while I shall let you know how it is.

[chipko]

Hi Steve thanks for update, must admit I was alarmed to read of your Scottish trip engine mount failure. Reading this, am I correct in assuming the brackets hadn’t actually snapped/failed completely?

We have a 2019 Mariner 20 version with a low 80 odd hours of somewhat spirited use. Have to admit was initially alarmed at amount of visible flex the mounts allowed…just a brief flick of the throttle in gear twists the motor down a good few degrees and it bobs about whilst hooning around in chop etc.

Must admit though have come to now quite like it. It’s not got any more excessive than when new and the damping is good for easing stresses on the transom. Another small benefit we’ve found is when winding on the power from standstill, the flex has the effect of trimming down the engine a tad so helping holeshot grip and letting us run trimmed out a bit more for optimum speed/ride.

Not sure if I now should be alarmed or not and wary of impending failure. Think I’d better have a word with Barrus and ascertain if there have been any failures or if a recall to fit stiffer mounts is recommended.

Thanks for posting this and hope your motor is now fine.

[Steve509926]

Hi Chipko,

Yep you assume correct. Hadn't snapped or failed completely, just very soft.

Like you, I'd noticed when I first got the OB that it appeared to flex more than other OBs I had seen, but really didn't think too much about it being new to the whole SIBing thing.
"Holeshot" - if that's quick up on the plane, then that's exactly what I experience all the time. Open the throttle and the prop seems to disappear under the transom for a split second, then away she goes!
I wouldn't be too alarmed. I think the service tech may have a point when he said pushing the OB hard that day. 9.30 though to 19.00 with a few breaks in between and I was at WOT most of the time trying to keep up with the big boys

[jeffstevens763@g]

I had the same with my Suzuki 25 it was shaking like a shi>>ing dog

[matt h]

Had exactly the same on my 2020 model from 0 hours on. Borderline dangerous, dealer said nothing wrong which is rubbish , it started flicking left and right at higher speeds so i sold it and bought new Yam 25 which was perfect.

[chipko]

Originally Posted by Steve509926

Hi Chipko,



Yep you assume correct. Hadn't snapped or failed completely, just very soft………I wouldn't be too alarmed……..I was at WOT most of the time trying to keep up with the big boys

Steve, bit confused here, apologies.

Now get it hadn’t failed catastrophically which is good news….I think.

However, did you notice it get worse suddenly, prompting remedial strapping, or just not realised how much damping there was until then?

With all due respect being at or near wot for extended periods should not be a contributory factor in engine mount failures.

Liking the super smooth damping on ours, it’s cushty, but not at the expense of premature failure.

PS: Just checked, moderate hand force moves the skeg +20mm forward and -15mm back. More movement under load though.

[Steve509926]

Originally Posted by chipko

Steve, bit confused here, apologies.

Now get it hadn’t failed catastrophically which is good news….I think.

However, did you notice it get worse suddenly, prompting remedial strapping, or just not realised how much damping there was until then?

With all due respect being at or near wot for extended periods should not be a contributory factor in engine mount failures.

Liking the super smooth damping on ours, it’s cushty, but not at the expense of premature failure.

PS: Just checked, moderate hand force moves the skeg +20mm forward and -15mm back. More movement under load though.

I can't say it got worse suddenly, as up until it happened everything had been running well, so there wasn't anything to get worse if you see what I mean.

We had crossed from Aaron to Bute and stopped just at the entrance to the Kyle's of Bute to let everyone catch up. Started off again, probably half throttle, rounded a marker bouy, opened her up to WOT and bang! Bouncing about like an unbalanced washing machine. Thought I'd hit something. Tried again at WOT, same thing, bouncing about.
Highland Haggis took a look and rightly suggested a problem with the engine mounts. He strapped the OB up as a precaution and followed me to our overnight site. Max revs I could get without feeling the OB was going to shake itself to bits was about 2500rpm
The next day, I managed to get back to Largs (Zander and Ronnie followed me in their RIBs, thanks again guys) under my own steam, but again anything above 2500rpm it bounced about. It was also affected by the wake of other craft and any rolling swell, a bit like a pendulum on a clock, so much so that a couple of times I had to stop until wake/swell subsided. Fortunately it was a very calm day, no waves or chop to speak of.
To be honest, it's not something I'd want to experience again.

I would say the skeg movement you have was very similar to what I had prior to the "failure"
After it went I could move the skeg a good 50mm forward and back.

[chipko]

Ok. Sounds pretty much like catastrophic failure from that description. Ouch!

Think I’ll get that call in to Barrus pronto. Cheers.

[Highland Haggis]

Hi Steve glad to here you enjoyed the trip and looking forward to seeing you on the next adventure.
Firstly the outboard should be able to run most of the day at wot or close to it without any issues we constantly do big trips where we are running nearly all day your engine mounts seem to be an issue that the developers know about and are having problems with this should have been a recall with all outboard with this batch and replaced.
Unfortunately they only do this if it goes to far with complaints and internet connection have helped spread the word.
I would have a look at your boat issue as well it seems to be slightly pushing the bow down into the water could of been because of the outboard issues but keep an eye on it for future trips and see if it’s not a fault with the boat keep us posted on your outboard mount repair and how she handles on your next trip all the best HH

[Steve509926]

Originally Posted by Highland Haggis

Hi Steve glad to here you enjoyed the trip and looking forward to seeing you on the next adventure.
Firstly the outboard should be able to run most of the day at wot or close to it without any issues we constantly do big trips where we are running nearly all day your engine mounts seem to be an issue that the developers know about and are having problems with this should have been a recall with all outboard with this batch and replaced.
Unfortunately they only do this if it goes to far with complaints and internet connection have helped spread the word.
I would have a look at your boat issue as well it seems to be slightly pushing the bow down into the water could of been because of the outboard issues but keep an eye on it for future trips and see if it’s not a fault with the boat keep us posted on your outboard mount repair and how she handles on your next trip all the best HH

Hi HH, I'll definitely be there on the next adventure Started preparing already - ultra lightweight chair bought, ready and waiting.

To be fair to the service tech, I don't think he was suggesting that the failure occurred because of the length of time at WOT. He was trying to suggest a reason why the OB had run OK for 60 odd hours with suspect mountings for it then to suddenly fail completely. The phrase "clutching at straws" springs to mind.

Hadn't noticed the bow issue before, but I suppose it's easier to see looking at and not sitting in.
I'll take a good look at that when I'm next on the water, hopefully going to West Wales mid Sept if I get the OB back in time.
Thinking about the geometry of where the prop is in relation to the transom with the OBs faulty mounts. I think it probably is to do with the OB as the prop will be sitting to far under the transom which, if I correct in the way I'm thinking, would push the bow down.
If it's not the OB that's causing the bow issue, any suggestions as to what else could cause it.?

[Poly]

Originally Posted by Steve509926

Started off again, probably half throttle, rounded a marker bouy, opened her up to WOT and bang! Bouncing about like an unbalanced washing machine. Thought I'd hit something..

Did it actually go bang? That doesn’t sound like the rubber being too soft that sounds like something more serious which the soft rubber makes obvious!

[Steve509926]

Originally Posted by Poly

Did it actually go bang? That doesn’t sound like the rubber being too soft that sounds like something more serious which the soft rubber makes obvious!

No it didn't go bang! I was speaking metaphorically. No noise, no jolt, no indication whatsoever, just very suddenly had a very bouncy, wobbly, unstable outboard.

[Brinormeg]

Bet there been a few stains after that one steve......scarey shit.... but at least you was with others to help out!

I've not any real clue as you know on sibs, but if not the ob causing the issue I dont suppose the trim has been moved from your usual set up?
"Trim angle too small and boat tends to plow and Trim angle too large tends to porpoise"

Bit of excitement with suspected boater yesterday opposite mull. Havent heard the facts though!

https://vimeo.com/589992473?fbclid=I...IG8YdwA3mvp61g

Oh and if your own ob not going to be back for your next trip can't the dealer/repairer under warranty give you another loan ob free or at least heavily discounted

[Steve509926]

Originally Posted by Brinormeg

Bet there been a few stains after that one steve......scarey shit.... but at least you was with others to help out!

I've not any real clue as you know on sibs, but if not the ob causing the issue I dont suppose the trim has been moved from your usual set up?
"Trim angle too small and boat tends to plow and Trim angle too large tends to porpoise"

Bit of excitement with suspected boater yesterday opposite mull. Havent heard the facts though!

https://vimeo.com/589992473?fbclid=I...IG8YdwA3mvp61g

Fortunately I had taken a clean pair of boxers!

Being with others certainly helped, and I can honestly say that HH calmed and controlled the situation well and put me at ease.

I was carrying more gear (fuel, camping etc) but I was lighter at the bow than usual because Diane and the dog didn't come. I do suspect the OB is the prevailing factor.

[TmMorris]

Good to hear progress is being made. Must have been immensely irritating.

I wonder if the clue lies in the fact that the softer mounts aren't per se an issue but that some turn out to be, ie it's a quality control problem for that batch of softer rubber and you got one or two of the dodgy ones that have somehow degraded rapidly whereas most are fine?

It might be interesting to ask the engineer to keep the old mounts for you so that you could see if there was anything obviously different about one of them? If only for your own peace of mind.

I can't visualise the mounts but for sudden collapse you would expect either a bonding to have failed, a rubber to have prematurely fatigued and a small split to have given way to a full split. Are the rubbers liquid filled? (Doesn't seem likely) and could one have split and leaked?

Do you know if they are replacing with a proven batch of the new type or reverting to the proven, older type?

[Steve509926]

Hi Tim, they are solid rubber and I think they have prematurely fatigued (some days I know how that feels )
My understanding is they are reverting back to the proven older stiffer mounts.
From the info I have been given, these softer mounts were to dampen down any excess vibration.
I think someone has got the compound wrong.

[chipko]

Originally Posted by chipko

Think I’ll get that call in to Barrus pronto. Cheers.

Ok, heard back from Barrus and pretty much exactly as advised to Steve;



“Thank you for your recent email. This isn’t a recall but If you are experiencing excess powerhead movement then we do recommend having the mounts replaced with the newer version - we normally see this on lighter, faster boats such as SIBs and small RIBs.
*
Short shaft engines are now built with an upper mount that is more rigid, an upper mount damper that limits upper mount travel, and a revised lower mount.
*
Your engine falls into the affected range……we will cover this under warranty.
*
I would suggest using our dealer locator and giving your local dealer a call to book the engine in, they can then order the parts ready for you”




Whilst we are not ‘experiencing excess powerhead movement’ (same now as when fresh out the box), think probably sensible to book motor in for replacement mounts. I’ve actually quite liked the floaty feel of the super soft original mounts but not at the expense/risk of premature failure out at sea.

As this isn’t (yet) a recall, big thanks to Steve for highlighting the issue. Hope other users see this, as any risk of premature engine mount failure feels like a serious safety item to me.

[mickter]

Does this fault only appear on 15/20 hp engines or does it affect larger engines,
I run a 2019/20 60 hp Merc with very low hours.
TIA Mick.

[Steve509926]

Originally Posted by mickter

Does this fault only appear on 15/20 hp engines or does it affect larger engines,
I run a 2019/20 60 hp Merc with very low hours.
TIA Mick.

My understanding is it only affects smaller short shaft outboards, however, a quick email to Barrus or call to your local Mercury dealer wouldn't go amiss.

[chipko]

Only applicable to the then new 15/20 efi motors methinks.

Our 2016 Mariner 60 hasn’t fallen off yet, unlike some Evinrude Etec 60’s where the saddles used to break.