Front motor mount adjustment

[mel low]

As I prepare my 86 for a four month 2'500 mile trip up to Alaska next month I pulled the boat and installed a new cutless bearing. I also replaced the shaft coupling hose. With the hose off I noticed that the shaft had been rubbing the lower portion of the fiberglass tube. I raised the back end of the engine to center the shaft in the tube. To re-align the engine I had to raise the front of the engine to almost the top of the motor mounts. This did not seem right so I had the mechanic from the yard take a look. He looked at the shaft coming up into the boat and said it was centered properly. He said the back motor mounts were set correctly. He said the front motor mounts may need to have blocks placed under them to raise them up. What could have changed that would have caused the motor to need this much of an adjustment?

[Craig Illman]

Out of the water? The alightment may be different if you're on jack stands vs. floating in water. The stern might have been sagging while on the jack stands?

Just a theory.....

[Ralph Masters]

I hate saggy sterns...

Ralph

[mel low]

Craig
I considered that and rechecked after back in the water. I was able to check the shaft location in the tube by feel after disconnect from the transmission. It was still in the middle in all directions. The engine is so high on the front mounts I can not put the second locknut on the shaft.

[Ken Juul]

I would venture a guess that nothing has changed, the factory just installed it slightly off.  After the boat has been in the water a week or so, check again to make sure it hasn't settled and changed the shaft postition.  If it stay's the same, much easier to add blocks under the front mounts than to change the tube angle. 

What second lock nut can't go on?

[Ron Hill]

mel : You didn't mention if the mounts are the originals or not. 
If they are you should change them out and maybe a differant mount will have a longer thread.   

[Stu Jackson]

What second lock nut can't go on?

In Ron's May 2006 Mainsheet article about repairing his leaky transmission shifter seal, there is a picture which includes his starboard aft motor mount, and it shows two nuts on the engine mount bolt.

I had our bolt on that same mount start backing off.  It'd been on so loooong that it had compressed the lock washer into uselessness.

I was able to match the nut at a local chandlery that has a great assortment of fasteners.  It's, IIRC, a fine thread metric nut - pretty hefty little bugger.  $1.52 + tax.

When I tightened the old nut down I found more vibration when running the engine, so I backed it off some and installed the second nut on top of it, keeps them both in place.  It's a real bear to get to it, and an adjustable wrench can only do 1/6th a turn at a time, only a 12 point box end would be better.

I only have one nut (besides me!  ) on each of the other mounts.

Lock nuts or lock washers or both, I guess.

[Ron Hill]

Guys : I recommended a second nut on the top of the engine mounts back in the early 1990s.  This "jam nut" keeps the primary nut from backing off - which is what happened to me!!

On my new engine mounts M25XPB I found that the jam nut isn't necessary because the nuts that Westerbeke mounts use are "peen-ed" nuts.  These nuts have much tighter fitting threads and as long as they are snugged there is no need for another nut.  However, I still made slippage marks with some finger nail polish to keep check - as a just in-case!!   A thought

[mel low]

Ron
I have only owned the boat for two years so not sure if the mounts have ever been replaced. They are the same as what I had on my 30. So I would assume they may be original.  I looked up on the Vetus web site to see if the 50 or 70 was available with a taller shaft but it did not look like it.  The front lag screws are loose so I may have to raise the motor to work on them so if I could find new taller mounts this would be a good time to change them out. But I'm still not quite sure why things are (or appear to be ) so far out of normal range.

The boat went back into the water on Monday so I will pull apart the coupling tomorrow night and remeasure everything and see if things have changed. Any idea who may have taller motor mounts?

[Ron Hill]

mel : If you have mounts that have a large aluminum looking base they are to originals.  Better yet look in the parts manual and you'll see the old mounts depicted.

I've changed mounts a couple of ways --  1. lifting the engine and 2. sawing the threaded shaft & then unscrewing the lag bolts (one mount at a time).  The later way, I followed Capt Al's idea of taking the new replacement Vetus mounts apart and then screwing the threaded shaft into position - it was worth a try and it worked.

The K75 Vetus mounts have a shorter base so you'll have to get differant lag bolts which will screw deeper into the engine bed and fix the "loose" problem.

Some ideas to think about. 

[Stu Jackson]

Engine mount repair, some other ideas:

http://c34.org/bbs/index.php/topic,5538.0.html

http://c34.org/bbs/index.php/topic,4611.0.html

[sailaway]

I also have a 1986 C34 my prop shaft also rubs the bottom of the log. It has for the 9 years  I have owned it. I don't like it but it has not changed in 9 years.  So I leave it alone. It has not hurt the log shaft. I think it came from the factory like that . Charlie