Yanmar 3ym30 when to change mounts

[Brahmany]

Hi all,
Hope someone here will know the measurements needed to decide if the engine mounts need to be replaced. Free standing sag or under compression? What to measure? Our little ym has jumped around forever and we just found out that the two back mounts are 75 and 100 instead of both 75. Has been like this since new in a Catalina. Contributions welcome Cheers

[GordMay]

Greetings and welcome aboard the CF, Brahmany.

If your engine mounts are more than five or six years old, or have been contaminated with seawater, engine oil or coolant, change them. The Yanmar manual says they should be changed every 1000 hours or four years, which ever is sooner.
Yanmar mounts are manufactured specifically for each side of the engine, so yours may be correct.

[Brahmany]

Thanks GordMay. The good book says A and B (front) are 100s and C and D (rear) are 75s. So I need to fix that up.
At 1,000+ for a set of mounts in Aus !!!!


On a lighter note: My dentist recommended I got all new golden teeth too. I think he may be related to Mr Yanmar Manual

I have read a 5mm figure but it doesn't say between which plates. Cheers.

[Captsteve53]

Since Yanmar mounts are so expensive you should look at the numerous very good quality (possibly even better than Yanmar) after market products, they will match the bolt patterns /height etc (just tell them what you have presently,

Actually the numbers Yanmar show tell you the Shore Hardness of the rubber with the 75 being in the soft/medium range and the 100 in the medium hard to hard range if using the Shore00 range, in the Shore A range it would be 75 as medium hard and 100 as hard to extra hard, there is a third range as Shore D as well, so most numbers will have either A,B or D after there quoted number

Many of the after market range have the same Shore Harnesses as original mounts but are way better at handling oil/water/corrosion etc,

Cheers Steve

[Alan Mighty]

Originally Posted by Brahmany

At 1,000+ for a set of mounts in Aus !!!!

I didn't realise you were in Aus.

Have you considered the alternative of Polyflex mounts? Made in Clontarf on the Redcliffe peninsula in the Moreton Bay Region (and so not a million miles from me) just N of Brisbane.

Have a look at: Poly Flex Group - Advanced Polymer Technology for Vibration Control - Y#2CTF Mount

or

work through the menu specifying bolt centres, min height, and stud size at: Poly Flex Group - Advanced Polymer Technology for Vibration Control - Mounting Systems

[jhulmer]

Brahmany
Just so happens I have a new set of these mounts( 2ea 75 and 2ea 100 ) that I bought about 3 or 4 years ago for my previous boat that I never installed. They have been sitting on the shelf and I was going to put them on ebay.

I don't know what the shipping is to Aus but if you are interested, private message me and we can work out a reasonable solution.

Jim

[holmek]

Try to find a Rubber Molding firm. In South Africa we have Specialised Moldings who will clean off the old rubber from your steel mounting plates and re-mold new rubber. They do engine mountings and all sorts of industrial equipment vibration supports. you can specify the hardness you desire. Yellow Pages for your area?

[holmek]

Meant to say , I have had mine done for one fifth of the Yanmar price and am very happy with the result.

[Fore and Aft]

I have Polyflex mounts on my Yanmar 2gm and are very happy with them. When they wear out you can just buy the new rubber inserts for them instead of a whole new mount. I paid $190 for each engine mount and $240 for the flexible coupling. That was two years ago.

Cheers
Drew

[Wotname]

Polyflex mounts also work upside down i.e. they will hold the engine securely in place in the event of capsize - unlike many other engine mounts.

[EmeraldCoastSailor]

How hard is it replace the mounts? Can I assume a reasonable DIY effort?

[holmek]

Yep, no biggie. Have a bunch of wood wedges and chocks handy, the engine will want to cant over. Jack it up with a scissor jack. Disconnect the shaft coupling. I unbolted the entire mount from the engine block and then worked on the bench. The biggest thing is to re-align the shaft once the new mounts are fitted. If you find the engine too heavy for you and a helper to man-handle, rig a tackle from the end of the boom as close to the topping lift as you can.

[Captsteve53]

As above post changing the actual mounts is the easy part, the hard part is getting the engine aligned with the shaft coupling an easy to follow description is here : How to Align Boat Engines | DoItYourself.com

This is a DIY but normally done the first time with a specialist and you take part or watch as if not correct all sorts of issues can result, even with flexible mounts it is important to have the shaft correctly aligned,

Cheers Steve

[rik stoney]

Originally Posted by Brahmany

Thanks GordMay. The good book says A and B (front) are 100s and C and D (rear) are 75s. So I need to fix that up.
At 1,000+ for a set of mounts in Aus !!!!


On a lighter note: My dentist recommended I got all new golden teeth too. I think he may be related to Mr Yanmar Manual

I have read a 5mm figure but it doesn't say between which plates. Cheers.

Hi there
I’m in the Uk
I have just purchased front and rear engine mounts for a 3YM30 engine.
From. Www.parts4engines.com.
£255 plus vat. £306 inc vat.
They ship world wide.
If you can buy them through a company. You will be able to claim back the vat or tax plus postage.

All the best Rik

[Frankly]

Because my 3GM30 is swinging a heavy Autoprop, I go thru motor mounts about every 5 years. Last replacement I opted for the stiffer 100s on the rear. Don't know if they will last longer but no noticable difference having the stiffer in the rear.


Frankly