Volvo Penta Md3 Motor Mounts

[Foreverunstopabl]

Hello everyone. I am finishing up my preparations for heading out to live aboard. My last serious issue is relating to the motor mounts. Take a looks at the mounts themselves. There is a stud that appears to be welded to the engine bed with a round rubber bushing with a hole in the center. The mounts as you can see are badly worn and in the rear provide no dampening. I have been to every marine store/surplus/boat yard and no one seems to recognize them. I need a solution sooner than later. I have read that there are two mounting types, "Hard" or "Flexible" These mounts appear to be hard. I would attribute the badly worn cutlass bearing that I replaced on the last haul out after my purchase of Hannah to the vibration caused under power as the engine vibrates transmitting that through the prop shaft and log to the bearing. Any and all advise would be greatly appreciated. I have thought about making my own from urethane bushings or auto body mounts and as a last resort using a hockey puck shaved to be in trans prop flange tolerance with a hole drilled in the middle in the mean time to finding a solution. Thanks in advance!

I know they are dirty, I'm cleaning out the engine bay next, just replaced the transmission and sealed the valve cover oil leaks.

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[MMNETSEA]

In circumstances outlined above, a number of steps would be normally required.

#1. Disconnect the transmission's aft flange from the prop shaft.

#2 Measure the height of the present engine mounts under compression,

mark position of the bottom nut.

#3 Jack up the engine and transmission.

#4 Remove the engine mounts and measure - uncompressed height of the mounts

#5 Note the difference between compressed and uncompressed.

#6 What is the weight of the engine/transmission?

#7 How engine many mounts?

Once 5,6 & 7 are known - come back - we then MAY be able to give a hand.

P.S. What are the bearers made of? Are they part of the boats infrastructure ???

[redbopeep]

Originally Posted by MMNETSEA

Once 5,6 & 7 are known - come back - we then MAY be able to give a hand.

P.S. What are the bearers made of? Are they part of the boats infrastructure ???

Agree with MMNETSEA that you need to get the info he suggests as you're not planning on going to a different engine mount system. After you have a bit of info, you should be able to take your dimensions and find a suitable replacement bushing for the existing mounts (or make one). I think you mean that the bars depicted/engine stingers are welded in place...or is a nut welded? The engine mounts should simply be bolted through to those stringers. And, the stringers soundly secured to the boat. If this is so, adjustments are made at the engine mounts for the alignment of the prop through the stern and cutlass bearings. If not, adjustments may be made at the point the engine mounts are attached further to your boat. This is a key question. The reason I bring it up is because your mounts look an awful lot like the little round puck-type mounts my Onan gen-set has. But, those mounts are permanently attached to the tray under the Onan and there is no way of adjusting them side-to-side just up and down.

If you measure all the clearances needed by your existing engine mounts and the size bolt used to mount to the stringer, you can also go directly to an engine mount manufacturer (also with weight of engine/transmission so they can figure which mount is best) or to a Volvo Penta Dealer (that is used to older engines) and find replacement, new, mounts. The new mounts are likely to have multiple bolts that you will use to fasten to your stringers and these bolts will allow you to adjust the 3D position of the engine/transmission so that your prop shaft is in perfect alignment with your stern and cutlass bearings.

We'll await your reply.