Last summer I replaced ALL the mounts on an Volvo MD17D. I was daunted at first by the task, asked lots of questions and when the mechanics I asked were too busy or refused to do it on a mooring
.. meaning I'd have to tow the boat... I bit the bullet and did it myself. It worked out perfectly.
Here's what I did:
Ordered and obtained the correct matching mounts. (expensive)
removed whatever was interfering with getting at ALL the bolts at the brackets and the mounts.
You do the mounts one at a time... remove and replace
To replace MOUNTS you remove the BRACKETS which are bolted to the engine block... THEN remove the mount.
Since you removed them one at a time the engine need only be supported at the one missing mount. Use wood blocking. You don't need a jack or hoist/sling to hold the engine!
Get the correct size wrenches. You might need a section of pipe to slip on the end for more leverage. Access is not easy.
To raise the engine if needed use a heavy crow bar
detach the coupling to the prop shaft
TAKE MEASUREMENTS OF THE ENGINE POSITION TO THE BULKHEADS etc. FOR FUTURE REFERENCE.
unbolt the top fastening / adjusting nut on the mount
undo the bolts connecting the bracket for that mount. Remove the bracket... (clean up and paint
??) Unbolt the 2 bolts holding the mount to the stringer and lift the mount off.
Now the engine is supported by 3 mounts and shored with some wood blocking
Slip the new mount in place. Bolt it down into the old holes in the stringer.
Now you place the new height adjusting bolt into the new mount - tighten height adjustment bolt.
Slip the cleaned up painted) engine bracket over the bolt and then bolt it to the engine block with the old bolts.
You may / should be close on the height... But that will be adjusted in the alignment of the coupling process.
If the other three mounts did not move and the engine was properly blocked the height should be pretty close. You do the mounts one at a time to keep the position of the engine as close the aligned with the shaft as possible.
Repeat for each mount and adjust the lower nut on the height adjustment bolt up to the bottom of the engine bracket.
It supports the engine!
Next pull the shaft and coupling forward to the matting part of the coupling attached to the engine transmission.
Rotate the shaft to get the bolt holes to align. Insert the bolts and tighten them slowly pulling the prop shaft/coupling closed.
If the coupling doesn't mate EXACTLY...you have to perhaps jimmy the engine with a crow bar until the coupling bolts align enough to grab the threads and begin to tighten. Once they align the engine is reasonably aligned with the shaft.
Use feeler gauge between the plates of the coupling to make sure the gap is uniform to the tolerance specified. If the gap is not uniform the shaft is out of alignment (slightly).Use a long crowbar with sufficient leverage to lift or jimmy the engine side to side or adjust the height of the engine mount bolts until the gap is to spec.
Check your engine position against your reference measurements. It should be the same as the REFERENCE MEASUREMENTS. If NOT YOUR ENGINE IS IN A NEW POSITION RELATIVE TO THE SHAFT
When you've got the engine in the old position AND the gap is to spec on the prop shaft coupling you dog down all the bolts - HEIGHT ADJUSTMENT BOLTS AND MOUNT TO STRINGER BOLTS AND FINALLY SHAFT COUPLING BOLTS.
If you got this right the dripless shaft (if you have one and not a stuffing box) will also be aligned and not drip water
. Alignment of the dripless shaft - no leaking - is another tell that your engine is in the correct position.
This takes time and patience but if I could do this... ANYONE can.
Take photos before during and after.
Your MAIN concerns are a leaking shaft seal and vibration from misalignment.
However, after the mounts were replaced there was no PSS shaft seal
dripping (proper alignment) and less vibration and noise
Mounts were expensive. Two of mine were broken.
Saved myself a few thousand in mechanic's labor and got the job done.
Message me if you have any other questions.
YOU DO NOT NEED TO REMOVE ALL ALL MOUNTS AT ONE TIME AND HANG THE ENGINE FROM ANYTHING. THIS IS NOT NECESSARY. YOU REPLACE MOUNTS ONE AT A TIME... SUPPORT ENGINE WITH BLOCKING AND USE A CROW BAR TO MAKE MINOR VERTICAL AND LATERAL POSITION ADJUSTMENTS.
The front and rear mounts are NOT the same part!