Changing Motor Mounts – Part 2

We left our last exciting episode on a cliff hanger. The fancy Polyflex mounts didn’t fit and were sent back. New mounts from American Diesel were winging their way to us.

The new mounts arrived. Bruce foolishly came back to help once more.

Here are the old and new mounts. The new mount on the left is American Diesel’s part number 831-0326.


The swap went quickly this time. We had it mostly figured out from the previous effort so I won’t rehash that. 🙂 We followed the same process. Lift up the front, swap the mounts, set it down, and move on to the next set of mounts. We were done with all eight mounts in less than two hours.

Here is a fancy new mount installed on the starboard engine.

The last part of the project was to align the engines on the new mounts with the propeller shafts. After reading threads on the internet, aligning the engines to the shafts is either a) easy to do yourself, b) something that requires skill and specialized tools, or c) a dark art. I am hoping it is somewhere between a and b.

We measured the height of the existing mounts and set the new mounts to the same height before we installed them. I expect the wear in the old mounts resulted in some sagging so it is likely the new mounts are slightly low. After that, I connected the shafts back up to the transmissions. The starboard shaft lined right up, the bolts went right back in without any adjustment. The port engine needed just a slight bump to port on the backend to get the bolts to slip in. Maybe a quarter of an inch. I used a 2×4 for leverage on the back end of the engine and tightened the mounts. When I was done, the bolts from the shaft slipped right in place. The mounts look straight and everything is tightened back up.

I think we got pretty close. At least as close as we could. A few hours of motoring around should let the engines settle in on the new mounts. Then someone that knows what they are doing can complete the final adjustment. We need to have the bottom cleaned so that will be good time to do it.

I started the engines up with the hope of seeing something wonderful. What I saw was both engines running with no shaking or movement. Close enough to wonderful. I really should have shot a before and after video to show the difference. Unfortunately, I always think of things like that after I start a project.

In the end, it was a pretty easy project. As is often the case, now that we know how to do it, we will never need to do it again. There is more than one way to lift the engines. This way worked for us. I wish the Polyflex bushings had worked out. They look like nice mounts. I wish we had the right parts the first time. That would have made things a bit easier. Brian at American Diesel was incredibly helpful. The mounts he sent fit just right. And as always, I could not have done it without Bruce’s help. We have known each other for going on 50 years now (that just sounds so weird to say) and yet he still volunteers to help when I need it. That is the definition of a true friend.

Now if it will just stop raining, I can get the boat washed down and cleaned up for Spring!

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