Noise from Stern Drive

[makoshako]

Back at the beginning of July our Mercruiser Stern Drive Alpha One Gen II had a serious failure at the upper unit where the gears ate themselves. It appeared that the oil had gotten low. My only suspicion about how the oil got low was maybe from hitting ground hard and possibly damaging one of the lower unit seals and letting the oil drain out. Anyway ...

In mid July we replaced our with the SEI 116 Upper and Lower Units.

A few weeks ago, we went out on our boat and were running at mid throttle, ~2500 RPM and were half way to out destination when a terrible and loud noise came from the stern drive area. I put it in neutral immediately checked it out and found that the unit would still go into gear (forward and reverse). We were a ways from help, so I also found that if I trimmed her up just a little that the noise was reduced considerably. We limped her back at idle speeds. The noise didn’t get any better or worse. Last weekend, I double checked the lubricant level and it was fine. I flushed the engine and the noise is still there. I am not sure what this could be … if I had to guess, it is either the u-joint or the coupling bearing. What do you think and what should I do?



Oh yeah and we followed the break-in process to a tee. Very strange. We weren’t even running her hard.

[Tech Support]

I suspect a u-joint problem if the noise changes when you trim up or down. You need to remove the drive and inspect the input shaft assembly. It is possible you hit something and damaged the u-joints or yokes.

Tech Support

[makoshako]

Thanks ... I will pull the drive off this weekend and inspect the input shaft. I am pretty sure I did not hit anything, although that was my first thought. The sound reminded me of hitting a crab pot and that was why I shut her down immediately. But, when I raised hew up, there was nothing there and there is no evidence of damage. We will see. Thanks again.

[makoshako]

We tried to remove the drive and inspect the input shaft assembly, but could not get the drive off. The drive seemed to have something holding it on and would not come off. We tried pulling it with a com-a-long and it would not move. We had ~1/8" move and that was it. What now?

[Tech Support]

Make sure you have the drive in forward gear. This aligns the shift shaft straight forward so it will slide out of the shift linkage in the bell housing.

Tech Support

[makoshako]

I did have the shift linkage in forward ... We went back to your installation instructions and followed them. Is it possible that the U-Joint has gotten out of allignment? If so, what can I do to get the drive off? Would it help to move the engine mounts slightly?

[Tech Support]

It is possible that one of the engine mounts could have broken or a stringer may have sagged. That would bind the input shaft and not allow the drive to come off. Another possibility (depending on how long the drive has been on) is water could have gotten into the bellows rusting the input shaft to the gimbal bearing. If you continue to have difficulty removing the drive call our technical department at 727-461-0811.

Tech Support

[makoshako]

I checked the engine mounts and they looked as good as new. The boat has been kept covered for its whole like and the bilge is in very good shape. So, I don't think that is the problem. The drive is brand new and the boat is not kept in the water. Basically the boat has been in the water long enough to break the drive in and a few hours. I don't think this the problem either, but since I can not get the drive off I can't completely rule this one out either. Since neither of these issues seem to be the problem, I used a little more force to try and pull the drive off with the cum along, but this time with chains. Still the drive would not budge. Is it possible that the cylindrical part of the drive that slides into the bell housing has been warped or miss shaped? The fact that the lube was leaking out from the bell housing/upper unit interface, makes me very suspicious that there is something wrong there. Is there some other way to get that drive off? I am running out of options and will have to take it to a service center soon. Thanks.

[Tech Support]

Please call our tech support at 727-461-0811 between 8AM and 5PM Eastern time, Monday - Thursday.

Tech Support

[cdjohnson]

How was this resolved?

I am looking at purchasing an SE 116 upper unit and am cautious of the support that can be given from a distance. I had a similar thing happen with my current drive and the problem was that the gear teeth fractured and came through the gear housing.
Was this drive replaced?

[Tech Support]

Every warranty issue is addressed to solve the problem. We either repair or replace as the circumstance dictates.

Tech Support