Cracked engine mount ...help !

[Dave-Fethiye]

One of the engine mounts that my Perkins Prima 500 sits on is cracked.

I have a picture of it which I shall try to attach.

Does anyone know what these mounts are made of ?

Do I have to have the engine hoısted out and replace it
OR can it be welded up in place ?

What would have caused the mount to crack like this ?

Any help - mosta appreciated
Dave

[Maddog]

I had to replace my mounts about 2 years ago. You can do it yourself 1 at a time. You want to replace that mount it is shot. You should probally do all of them. Use a hydraulic jack, 2x4's whatever to lift each corner one at a time and swap them out. Check harbor freight for the jack. they ahve several differt models and attachments. be sure to realign to the prop shaft afterward. Thats the fun part.

[DeepFrz]

Usually engine mounts are bolted to the engine bearers. Maybe welding them on weakened them and caused the mount to crack.

[Dave-Fethiye]

Thanks for the replies.

The engine mounts are not welded on - they look like they are bolted on.

It looks like its made of alloy ???
It seems to have corroded differently from the steel part above it.
Shouldn't it have rubber in it ???

I just thought that if the mount is steel then I could weld up that split.
Of course if it has got rubber in it I can't do that anyway - but it lloks like a block of alloy. Any one know what its made of ?

[DeepFrz]

It should contain an elastomeric compound (rubber?). That is what keeps some of the engine vibrations from being transmitted to the hull. Although I have no idea what yours are made of. Do a search for engine mounts. There have been a number of threads discussing them on this forum.

Actually, if you look down at the bottom of this page you should see a number of links to different engine mount threads.

[delmarrey]

Welding? Don't even think about it!!! What do the rest look like???

From what I see you should pull all the mounts and their brackets and have the brackets sandblasted and analyzed. If your going to replace one mount, you might as well do them all from what I see there. The chances are your motor is already out of line.

That type if mount is around US$40 each. If you boat ever gets a blow down or, God forbid, a rollover $120 + labor is cheap insurance.

The base is aluminum with the poly insert cast around a grade 5 steel mushroom stud.

Some of the new ones now are using a composite rather then the aluminum.

[Alan Wheeler]

Del's spot on. Replace all, even if the others look OK. Corrosion has caused it to crack. They are well and truely past their use by date. The main brackets need removing and cleaning and painting as well. When reinstalled, paint to bolts to protect against corrosion . If the mounts are identical to the old ones, in diamension that is, the alignment should not be required. But it will certainly be out at the moment.

[rtbates]

There IS rubber in there between the steel engine bracket and the alloy mount where that big fat vertical bolt is going. I can barely see it. It's totally wasted and compressed. Probably allowing the steel engine bracket to come in contact and stress the alloy enough to crack it. At any rate it is beyond shot. Replace all four. Looks like it spent more than a little time under water!

Good luck.

[GordMay]

Originally Posted by rtbates

At any rate it is beyond shot. Replace all four. Looks like it spent more than a little time under water!
Good luck.

Which suggests a good examination of the pictured wood timbers adjacent.

[Jesse Holden]

All the above is exellent advice but be sure to disconect and seperate the prop shaft coupler at the gearbox first. Please don't ask me how I learned this.

[cooper]

Aw go on Jesse just a little hint...... ; )

[senormechanico]

Originally Posted by Jesse Holden

All the above is exellent advice but be sure to disconect and seperate the prop shaft coupler at the gearbox first. Please don't ask me how I learned this.

How's this for a hint?

(Blub blub blub)

Steve B.

[starfish62]

That looks like cast aluminum. Or Aluminium for the Kiwis, Limeys & Ozzies out there. A big rubber or edpm foot would help dampen vibration quite a bit. If you've got a trucker's supply place or R/V dealer close by, I'd check them out rather than the usual suspects. Get a big rubber foot with threaded rod and nut adjustments, and take care that the shaft is lined up correctly and that the block is level. The new mounts should be a nice improvement! And ignore what Jesse said about cutting the shaft coupling lose, the Aussies are just wannabe Kiwis and rarely get off of the lakes.

[Celestialsailor]

When ever you do anything to the mounts...ALWAYS CHECK THE ALIGNMENT. Chances are it will be off. Even as mounts age, alignment can drift. I check mine about every 2 years.

[Alan Wheeler]

the Aussies are just wannabe Kiwis and rarely get off of the lakes.

You just have to be an ex Kiwi to be able to make a hard hitting tongue in cheek comment as good as that. Or you were around one waaaay to long. ;-) :-)