Engine Mount Rubber Replacement

[mjt]

Hi all.

I need to replace the rubber on my Yanmar 2QM20 engine mounts, one of which is pictured below.

I have been unable to identify the type of mount. It seems that I should be able to cut some of the right kind of sheet rubber to size and shape and bolt it on.

Has anyone tried this? I want to avoid buying new mounts.

Cheers

mjt

[Inthewind]

If I were you, I would not skimp on motor mounts by trying to fabricate your own. 2QM20's vibrate alot at idle and take thier toll on engine mounts. Your better off fixing with new mounts and you should be good to go for around another 1000 hours or so, Yanmar says to replace only after 500 hours. Here is a place you can go for many parts for your engine.

QUICK REFERENCE FOR SPARE PARTS & SERVICES

[Alan Wheeler]

The rubber is bonded to the metal fixture. You can't simply replace the rubber. It means new mounts sorry.
To add, I am not sure if the metal has lips internally ion the rubber, but most marine mounts are such that if the boat tips over, the mount is captivated by the metal and not reliant on the rubber bond to the metal tags to keep the engine in place.

[mjt]

Thanks guys.

The engine is/was bolted to each mount with two bolts, the rubber being sandwiched between the engine mounting lug and the top of the mount with those bolts going through two holes in the rubber, into the threaded holes visible in the photos. Sandwiched, that is, until it was worn through completely on two of the mounts during the previous owner's tenure.

The mount is then bolted to the bearers with another two bolts per mount.

As pointed out by Alan, the rubber is bonded to the metal but the above system of bolts seems to make that superfluous - the pad is captive.

I'll look more closely at the purchase option which, apart from cost, may mean drilling new holes in the bearers for the new mounts. (So far unable to locate similar mounts.)

[BilgeRat]

Those look like automotive motor mounts. The rubber is volcanized (sp) (casted together). I'm not sure I'd want to duplicate what you have.

Is there some other means of adjustment? Most marine mounts have sliders or jacking screws.

I think I'd contact Yanmar to see what they recommend.

Yours Aye!

[merlin]

I'm not sure if this will help you, but I know that when trying to replace automotive motor mounts, it is very common to cut out most of the rubber and then "fill" the mounts with polyurethane. You can buy it at mcmaster carr in different shores. Most people use 80 shore. The benefits are cheaper, the downsides is polyurethane is usually stiffer so you get more vibration. In an automotive application stiffer mounts means more power to the wheels.

Just through I'd throw that out there for what it's worth. This page might give you some ideas depending on how experimental and risky you want to be

Eliminate Wheel Hop with Filled Motor Mounts

Of course, I have no idea how this would work for this application but it's just more of an idea than anything else!

[mjt]

Thanks for the leads.

[Steve Kidson]

Polyflex manufacture a range of engine mounts for most applications. You just need give them the engine make and model, and they can usually work it out from there.

They are in Brisbane, and their website is Poly Flex Home Page

Fair winds

Steve

[mjt]

Thanks Steve - Polyflex looks great and just the right location for once!

[CaptnBob]

I agree with Inthewind, and also that those do not look like Yanmar mounts.

Yanmars mount technology is the best. And they do need replacement, their rubber tends to be very "lively" but they are very effective. In fact for the 2GM series the fore and aft mounts are of differing density, and be careful to install the correctly.

I have read on other sites (e.g. Boatdiesel.com)of people causing damage to Yanmars by installation of non Yanmar mounts which result in excessive engine vibration.

Rem you will need to realign the motor and drive train.

[cat man do]

Originally Posted by mjt

Thanks Steve - Polyflex looks great and just the right location for once!

You could also give Diecon engineering a call

Welcome to Diecon Engineering

I got my Cummins 3.3 X 2 from them and they have a Polyflex look mount [identical] that has Diecon stamped on them, so may be more affordable.

They are closer to you as well.

Dave

[mjt]

Well, this will have to wait now as I'm overseas for a couple of weeks (the easy way). Thanks to all for the info.

Unfortunately I'm constrained as the engine is about the third one put into this old boat judging by the number of holes drilled in the bearers. The height of the engine mounting lugs (which have been cut off and redrilled to suit the bearer width and low profile bearings) above the bearers when the engine is properly aligned with the shaft is quite low so I believe that I'm going to have to be creative about my final solution.

I certainly hear the recommendations to go for Yanmar mounts and the potential serious consequences of a mistake, but in this case it seems that those structural constraints will dictate otherwise.

I shall digest the facts in long term subconscious lateral thought mode.

[Brent Swain]

When a friend installed a new yanmar , it vibrated uncontrolably. When he told Yanmar he wanted harder mounts they said it would void the warrantee. I posted the warning to avoid Yanmar diesels for this reason, on every chatline I could find. When he sailed into Singapor, a yanmar rep pulled alongside in a skiff, replaced all his mounts with proper , hard ones, realigned the engine, then wished him luck and left. The internet works.
They are unaceptably soft , have nothing but rubber between you and having a diesel rolling around int he bilge.I've heard many stoiries of this happening.They are dangerous. Get some hard perko mounts with metal between the rubber and the bolt.
Thje cruising grounds all have their share of Yanmar mount problems. They are made for weekend cruisers only. They are grossly overpriced for a grossly inferior mount. Avoid them like the plague.
Brent

[never monday]

Brent,
Let it be know; I am a Yanmar dealer and have been to many Yanmar schools.

Yanmars mounts meet all the ABYC requirements for engine mounts. The EU and other countries might have rulees I'm not familiar with.
I have never seen a Yanmar mount seperate. Yanmar mounts when installed IMPROPERLY will cause severe vibration.
Yanmar mount ARE a service item. They should be replaced every 5-8 years. Sooner if saging or degredation from fuel is noticed.

You are entitled to your oppinion, but continuing a "story" in the second or third person does nothing to help the situation or better the product.