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Motor Mounts

PostPosted: Sun Nov 11, 2007 2:32 pm
by alan
Several months ago, a fellow Highlander flyer, James, from Halletsville, TX, asked me if I had had any problems with my motor mounts. I had not, then. I do now.

The other day, I visually checked them again and noticed the port side front mount was starting to deteriorate. Just Aircraft gave me the part number and I ordered a complete set of 6 from Aircraft Spruce. I had flown maybe 10 hours more by the time they arrived and the time was right to replace them. By this time that mount was almost totally gone. Not the top, just the bottom. The next one back on the port side was just cut around the core and the front starboard mount was the same. The rest looked new. I did replace them all, about a three hour job with a chain fall to raise the engine.

This was Friday afternoon and Just was closed. I will call Monday and ask if this is a common problem. If this happens again, I believe I will try to fit more robust mounts in place. Two Highlanders with the Rotax 912ULS with motor mount problems is not an epidemic, as long as it doesn't happen again. If it does, these mounts aren't correct for the application.

Alan N1010Z 165 hours in 16 months.

PostPosted: Wed Nov 14, 2007 10:24 pm
by n570k
Private e-mail me [email protected]

PostPosted: Fri Nov 16, 2007 10:54 am
by alan
I replaced my motor mounts, P/N BM002, last weekend and talked to Tim Monday. He said there has only been one problem reported, besides mine, and it has to do with properly inserting the rubber mounts into the aluminum angle. I just need to oil the rubber and then twist them around to insure a flush fit. I think I did that this time, but I know I didn't the first time. I remember having a difficult time getting them in the hole because I didn't oil them first. Maybe it will be OK now.

Tim told me that Jim in Halletsville had the same problem but has gotten it fixed. I talked to Jim today and he said he still has the problem, so maybe there is a different problem. I am going to fly over and see him soon and we can more properly compare notes.

Dang! Another reason to fly.


PostPosted: Fri Nov 16, 2007 12:26 pm
by Uwe Jens
I prefer not to use oil or any petroleum derivates to lubricate any type of rubber that is not specially made to be in contact with oil (like a seal).  As time goes on the oil could degrade the rubber.  It is better to lubricate with any kind of vegetable grease (margarine or cocoa butter) this helps the rubber not to loose its┬┤properties.   :idea:

PostPosted: Sat Nov 17, 2007 1:21 pm
by alan

Live and learn. Maybe next time.