Engine mount replacement ?

Boats&Outboards · 02 December 2011, 10:30

Product - Mercury 60hp 4 stroke 2002 Carb model fitted to fishing boat

Problem - worn lower engine mounts, top ones are perfect. Both lower mounts have excessive play - quoted £750 to replace via local Engineers. Fair enough

Solution - over to you????

The lower mounts have come away from the steering tube. Looks like the chemical bonding has given way. The mount themselves look ok but of course they are not available to replace without buying the entire Steering tube. That's not a problem but I'm looking at trying to repair without the need for powerhead removal.

So any ideas ?

I've considered trying to source mounts such as torsion automotive suspension bushes and pressing them into the bracket. It's not trying to do a bodge job or anything I'm just interested in seeing if there is a different option to powerhead removal as I get lots of older motors offered in with worn mounts that I pass on because it's not worth the time trying to get powerheads off 20 yr old motors with rough bolts. If this idea was to work it may change things a bit. Not sure the thin Ali mount holder will take the strain of pressing in though.

Anybody have a better idea

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

Sea Witch · 02 December 2011, 11:07

I have mariner 75 1987 , my lower mount bushes went , same situation didn want to remove power head ,so I cut d 2 bolts out using hacksaw and change lower mounts and used stud bar with 2 locking nuts , there still there today working perfect

Boats&Outboards · 02 December 2011, 11:52

The mounts are removed. The bolt comes out as its the bonding which holds the mount in place, the bolt links it to the mid-section.

I can refit the bolt once we've worked out how to get a mount secure back in place

diver 1 · 02 December 2011, 13:10

They are a pain in the neck and can be very time consuming to replace. I recently changed all 4 mounting bushes on a pair of 1989 Mariner 40 engines.

I looked at as many options as I could think of and spent a long time searching product catalogues trying to find similar mount bushes from the automotive industry as well as contacting several busing manufacturers and sending them photo's and sketches of what I required.

In the end I gave up and bought new mounts (discovered that Yamaha ones are cheaper than Mariner ones..) from Bill Higham Marine (cheapest I could find)

I stripped the engines (snapping a few bolts in the process) and replaced the mounts, replaced all the gaskets and carefully extracted all the broken bolts and replaced them.

It took me about 2 days in all being very careful to strip and rebuild the engines.

They were much better afterwards though. Heck of a lot less vibration. (3 of the mounts had sheared as your describe, the rubber had perished and split on the others).

Good luck

Boats&Outboards · 02 December 2011, 16:06

Quote:

Originally Posted by diver 1

They are a pain in the neck and can be very time consuming to replace. I recently changed all 4 mounting bushes on a pair of 1989 Mariner 40 engines.

I looked at as many options as I could think of and spent a long time searching product catalogues trying to find similar mount bushes from the automotive industry as well as contacting several busing manufacturers and sending them photo's and sketches of what I required.

In the end I gave up and bought new mounts (discovered that Yamaha ones are cheaper than Mariner ones..) from Bill Higham Marine (cheapest I could find)

I stripped the engines (snapping a few bolts in the process) and replaced the mounts, replaced all the gaskets and carefully extracted all the broken bolts and replaced them.

It took me about 2 days in all being very careful to strip and rebuild the engines.

They were much better afterwards though. Heck of a lot less vibration. (3 of the mounts had sheared as your describe, the rubber had perished and split on the others).

Good luck

Sorted today. My guy done well. He's retro fitted stronger bushes in the insert of the existing mounting location, To prevent it simply slipping in/out of the tube he has added an additional 2 bushes either side of the mounts. It now has two solid lower mounts with 4 bushes (2 on each mount) which we hope will take up any movement.

We will be fitting them in tomorrow after giving them a final check over and buying some stainless steel washers to protect the mounts further.

Once done we will be doing a sea trailer and then checking for any play. By the looks of things it's going to be far stronger than it would have been had we removed the powerhead and fitted a new unit!!!

One to remember for the future. Just saved £800 which of course will be passed on to the customer :whistling

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

jyasaki · 02 December 2011, 16:12

Peter:

Out of curiosity, were the nuts on the lower mounting bolts brass or stainless?

A buddy of mine just had the lower mounts fail on his 2005-ish Merc 60EFI due to the brass nuts corroding away. The stainless bolts were fine, and the rubber bushings were hardened, but serviceable.

Just wondering if they've always done that (dealer said something about anodic protection for the bolt, though I don't see an advantage if it still fails.)

jky

Boats&Outboards · 02 December 2011, 16:13

They were Brass but they did not fail. The problem on these was down to the bonding coming away and that was down to poor control by the previous owner using Reverse too heavy at speed to stop the boat.

I'll get some pictures of the repaired mounts once it's back together.

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

PeterM · 02 December 2011, 16:13

Peter - any chance of a pic of the 'fix' ?. I have a mate who I think is facing a similar situation ....

Pete

Boats&Outboards · 02 December 2011, 16:18

Once it's back together and gone through some sea trials I will upload the pics.

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

Turbodiesel · 02 December 2011, 19:56

Problem - worn lower engine mounts, top ones are perfect. Both lower mounts have excessive play - quoted £750 to replace via local Engineers. Fair enough

You didnt ask us for a quote thats why!!

Boats&Outboards · 02 December 2011, 21:22

Quote:

Originally Posted by Turbodiesel

Problem - worn lower engine mounts, top ones are perfect. Both lower mounts have excessive play - quoted £750 to replace via local Engineers. Fair enough

You didnt ask us for a quote thats why!!

How much would you have quoted ? It may not be resolved just yet!

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

Boats&Outboards · 07 December 2011, 17:59

Ok pictures as promised.

Bearing in mind this is not a final repair. We aim to put the boat on the water tomorrow for testing then will buy new mounts/bushes to replace what we've fitted at the moment (from a vast array of leftover car mounts etc). We will also be machining down the stainless washers to the same diameter as the bracket, to ensure a natural looking design.

From the initial testing we have done its far superior to the previous system. Also it benefits from being able to be removed, replaced or even just adjusted to account for "wear", which the previous system never had. I see no reason for this not to be a better option for repair in place of removing the powerhead!

Parts used were as follows (required for each side/mount)

2 Torsion suspension bushes (not visible as located within the lower tube housing)
2 Suspension bushes
2 Large stainless washers, (machined out to same diameter as the mounts)
2 Small stainless washers
1 Stainless Bolt (130mm length M10 - 10mm diameter)
1 Stainless Locking nut (17mm)

You will need the existing stainless frame which connects the mounts behind the leg. This part will never fail

The theory is the main mount (hidden, we decided against a perfect fit press in type, instead went for a "tight" fitting and use washers to secure) will still take the strain, to prevent it simply slipping in/out the large washers act as a stop each side of the housing (this does the job of the "chemical bonding" was failed causing the fault). The extra bushes take up the slack and assist in taking the strain/vibration. The final, smaller washers prevent these from crushing up on the bolt.

Total cost will be about £25 in Parts (when bought new, current cost about £8 using what we had). Labour around 1 hour to devise, test, adjust, fit, re-assemble cowling.

Total saving = around £700 dependant on quote! Obviously had the top mounts had any signs of wear then this is not a suitable repair and you would need to replace the entire unit. If like ours thy were perfect and it's just the lower mounts that were shot, this will resolve that problem.

JOB DONE...I hope

Peter ~ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007