Bosn Mate":2r8gl8a7 said:
Brian:
I have appreciated your posts on Tugnuts and assistance when we met in 2022 at Sweetwater Landing Marina.
I read your posts on this topic and would like your guidance on what a hands-on, but not a professional mechanic, should be doing regarding motor mounts and checking alignment. I have treated the motor mounts to protect against rust and added a shield to contain seawater from the shaft getting all over the engine. Nothing more beyond that.
So...what should I be doing on a regular basis vs taking to a trained professional. For example, should I learn how to align the engine? If so, what source can I access to learn how? I prefer to do as much as I can but I also recognize that some tasks are better left to the pros. I just can't figure out where the line is on this topic.
Look forward to your reply!!
Mike
Mike'
Motor mounts don't require much maintenance. I like to know that I have a stating point when it comes to motor mounts and engine alignment. Once you have a known starting point the maintenance protocol is keep the mounts clean and rubber components oil free, inspect the lag bolts fastening the mounts to the engine stringer grid. Confirm bolts are in good condition and tight. Inspect all motor mount fasteners for tightness.
Starting point can be a question. Bottom line any new boat or used boat that is purchased an alignment history should be noted. Who aligned the engine/shaft/train? What was the final alignment measurement that was accepted ? The specification is .001 for each inch of coupling diameter with a maximum of .004 of angular misalignment. 6 inch coupler .004 max, 4 inch coupler .004 Max. Rule of thumb is max .003 or less is what we shoot for. Just because the boat is new do not take for granted the train is aligned. It needs to be checked and documented. This is your starting point. You know it is aligned, all components are running in a straight line. Now all you have to do is make sure everything stays in alignment. Fasteners tight, motor mounts are in good visual condition. Simple maintenance. Marking the nuts with marker , paint or I use red lock tight. This gives you a witness mark. If something moves you can verify the movement.
If you don't have an alignment history. How do you know if the train is aligned? I have heard folks say it is aligned because it doesn't vibrate. Ok maybe?? Is it aligned to spec? Bottom line you don't. Once it is aligned you do and if you maintain the hardware it should hold a good alignment for years if nothing is disturbed.
When I purchased my C26 New I was told the alignment was checked by the dealer. I took his word for it. I didn't notice a high vibration. I used the boat for two years until I found out it was out of alignment. Loose nut? Was it aligned from the dealer? Was the nut loose from the beginning? I don't know because I did not check it or have it checked. I had no information other than. Yes it is aligned. Once I completed the alignment. I Knew it was aligned. I checked the mounts from that point on and never had an issue with packing, vibration, cutlass bearing. It all seemed to be in good shape.
When I purchased my Mainship Pilot I was told that a service technician had replaced engine mounts on my port engine. Great!! New mounts!! I took delivery and piloted the boat to its winter storage destination. This was a 180 mile trip, Lake Michigan to the Illinois river. I did't know this boat's running characteristics but I did know I had something going on with the port engine. When on plane I could hear and feel vibration. My wife could not, she loved the boat. When we got to the marina I checked alignment before the boat was lifted for storage. Both engines, Starboard was spot on. I could not slide a .003 feeler gauge between couplings. Port engine a loose .009 so .010 gap. When I inspected the mounts I found all mount nuts tight but the mounting bolts holding the mounts to the stringer brackets were loose. The tech I believe aligned the engine but forgot the final step, snug all bolts tight. I aligned the engine and took it out for a sea trial. What a difference!! Much better but not perfect. The boat was lifted and put in a building. I checked the Cutlass bearings again. The surveyor checked them when I purchased the boat and checked Good. Not really!! There was more play than I liked. I replaced the bearings, checked the shafts for runout, sent the props out to be balanced, installed new shaft seals. When the boat was launched I rechecked the alignment. It was off a little because of new cutlass bearings. I made a couple of moves and locked it down both engines less than .003 angular misalignment. When I sea trialed the boat I got what I wanted. No shaft movement, no vibration, much quieter when running at high speed. ( It's still noisy with two 4cylinder Yanmars spinning 2800 rpm under my feet) But much better. I did the Loop, 850 hours later and almost 6000 miles under my keel. Nothing has changed. I had a starting point and all I had to do for engine mount maintenance was visual inspection. Nothing moved!
If you want to do alignment yourself. Go for it, once you have completed the task you will understand alignment better. You will then know it is aligned and maintaining alignment will be easy.
If you want to hire someone to check it watch him do the checks. Ask for a minimum misalignment of .003. You now know that it is aligned and all you need to do is visual inspections
If you think the alignment is good and you are comfortable with just leaving it alone. Keep doing what you are doing.
This is a good guide
https://www.google.com/url?sa=t&rct=j&q ... i=89978449
