DuoProp Groan while trimming

[Bigghauss]

CC et cal.,
I have a 2014 Cobalt 220s with a DuoPro. I've noticed that after running it for a while, when I go to trim down the out drive I hear a noticeable groan coming out of the system. It ONLY happens after I've been cruising for considerable time at higher RPM's (3200+). So for example, as i'm just tooling around, pulling tubers, or whatever, the trim has no sound. But if I go for a 15+ minute cruise at speed, and then trim back down when I slow down, their is a clearly noticeable groan.

I never hear it when the system is cold. Never hear it after running for short periods of time, only after having dialed in a good rate of speed over a period of time. I noticed it this past week while up at Lake Powell. I ran up lake to find an anchorage and so I dialed in about 3200 RPM's and trimmed accordingly and ran for about 35 minutes non-stop this way. As I was pulling closer to our possible anchorage I backed off speed to under 20 MPH, and started to trim down when the groan starts. As if the drive is laboring to be trimmed down or something. I can't figure it out. Fluids looked good. And again, when cold, or moving through variable speeds, it doesn't seem to do it.

Any thoughts on this????

[cmattj]

Have you listened for the noise not running once warm? I ask because groan failure of one trim ram or pump may be occurring. As to isolate an internal issue such as engine alignment... u joint slipping in the caps to one side etc.

[Howl Yes 242]

Read my recent posting... mine was doing same thing and the tilt cover was leaking, thus sucking water in and contaminating the fluid. Mine was leaking around the bottom two bolts.

[Bigghauss]

Thanks for the ideas! I'll check it out this week/weekend. Good points to consider. The alignment comment...hmm...does that happen often?

[Bigghauss]

Update for my DuoProp Groan: So I picked up my boat yesterday from service. It has about 62 hours on it and my mechanic said it was immaculate inside. Clean oil, no water, all my fluids looked great. Filters were clean, so not making any metal. He was very impressed. So anyways, I told him about the groan. He felt that since it happens right after being under load, that as I'm trimming it down, the splines were under load from the high speed, high trim setting and thus the trim motor is having to put in a little extra work (ie: Groan) to bring the trim down as the splines are under load and thus lots of friction. This manifests itself as a more audible trim motor. This load is especially greater on a new out drive as there is no slop in the newly machines parts. He asked me to try, in an effort to troubleshoot, to unload the drive BEFORE trimming it down after I've been running it hard. If the groan goes away, he feels that this is the issue and there isn't much he can do as it was all greased up nicely, with no abnormal wear or alignment issues. Again, it might start to calm down as those parts break in more and more. He didn't see any problems with my rams, all the hydraulic plumbing, or the motors themselves, so tough to pinpoint.

Seemed like it made sense as he had another DuoProp in the shop that was opened up and he showed me what parts were under load at higher trim/power settings and what happens when I trim it down. He moved the outdrive through it various positions and explained where the shafts are loaded up, and that the trim motor is trying to overcome those forces as it trys to push the out drive back down. So, I feel like I got a pretty plausible answer and I'll try it out next time i'm at the lake.

Feel free to chime in with your thoughts. My mechanic has always done right by me, so I don't feel like I'm getting a runaround.

[Howl Yes 242]

I am not an expert, but mine is making the same noise and it has water in the system from a trim pump cover leak. I would suspect that to be an issue, but you mentioned he gave you the all clean on the fluids. I have a hard time going with his input because who in their right mind would accept that level of noise all the time? That is a design flaw to me.

I got a new cover from Volvo for free and will have it swapped out soon. I'll let you know how it goes.

[Bigghauss]

How did you get a new cover? Did you contact them directly through their help line? Any pictures or advice on whats needed to swap this out?

[Howl Yes 242]

How did you get a new cover? Did you contact them directly through their help line? Any pictures or advice on whats needed to swap this out?

I contacted the Volvo Penta customer service line and they opened a ticket for me. I then got an email conversation started with a rep. After sending them details and a written estimate from my dealer/authorized Volvo service location, they informed me of the decision to send me a new cover kit. I also made mention it was a known Volvo issue based upon the number of incidents online, etc. You can internet search for the cover kit and find a few HOW TO articles and videos.

I hope this helps.