[Yellow Jacket]

2006 SX19, 4.3L V6 MerCruiser.
Struck a submerged log a year ago. Broke the gimbal ring, a lot of the anti-cavitation plate, the skeg, and badly bent the prop. Replaced the entire lower unit with an SEI SE116 lower unit. Put on a new Rubex prop. Boat runs well now, but there's a fairly loud whine that seems to come from the sterndrive when the boat is underway (only when going forward). (There is no whine when running on the trailer with muffs.) It does not seem to be noise that will go away with break-in of the lower unit. Mechanic thought the noise was coming from the upper unit, which was not replaced. He found a bearing with an odd wear pattern on it and thought that might be the source of the sound. He replaced the bearing and checked out the entire sterndrive, upper and lower unit, and said it all looks perfect. Put the boat in the water for a test drive -- the whine is still there! Any ideas?
Thanks,
Yellow Jacket

[ColoradoDiablo]

Is the engine/drive alignment good?
Does it whine all the time , or just while turning? Bad Gimble bearing?
I had a coupler on a Cobra that was bad and would whine like that also.
Just a thought or two.
Keep us posted.
Larry

[Dredd]

SEI drives whine, it's a known "issue". They have support forums and there is some talk about it. The techs on the forums say to break them in properly then just keep running them and they'll quite down a little. I have read that with my own eyes but don't see it at the moment. One thing I have posted here at the MOC before when it's been brought up is this link though, see post #7. It's basically the same thing I read on SEI's site once.
SEI Sterndrive - The Hull Truth - Boating and Fishing Forum

[Yellow Jacket]

ColoradoDiablo: I have not talked to my mechanic specifically about engine-drive alignment but I guess it should be OK. The engine is new long block replacement due to a cracked cylinder and he installed it as well as checking out the sterndrive. It whines all the time when in drive, not just while turning. Gimbal bearing was replaced too.

Dredd: I have been breaking in the SEI drive slowly, but it has been a lengthy process because of the engine replacement work due to freeze damage. I estimate I put only 10 hours on it last year and only 12 this year so perhaps I've got a way to go. The SEI rep did say that the whine should lessen (when I called him a year ago). The fact that it is still fairly loud during and after the 12 hours I've been breaking in the new engine is a bother. Thanks for the Hull Truth link -- good to see that many people are pleased with SEI drives, and that others report the whine too.

It's principally that my mechanic says he's not heard a replacement lower unit have this kind of sound during break-in. Now that the boat is put up for the winter, I suppose all I can do is see how it sounds next year and keep my fingers crossed that the whine will decrease.

Thanks for the replies,
Yellow Jacket

[ColoradoDiablo]

Good to know about the SEI drives. Look forward to hearing from you YJ on how things go in the spring. Sounds like maybe a little more time on the drive be the ticket for you.