Popping noise when lowering outdrive

[ratdude747]

Noticed a weird popping noise when lowering my outdrive (MC-1 888) after I got home from an outing today. See video.

Is this normal? If not, what would cause it? I did hit a bit of wood today, once hard enough I thought I nailed the prop (but the prop, despite being plastic, only had blunted/scraped leading edges). I was trimmed slightly up when that happened. I hit some more wood lighter at idle speed with the drive at trim cutoff (shallow creek leading to boat ramp).

 

[Bt Doctur]

sounds like the rubber bushings are too tight or dry.other cause is tight seals on the ram ends. More common with those rams vs the newer type

 

[ratdude747]

sounds like the rubber bushings are too tight or dry.other cause is tight seals on the ram ends. More common with those rams vs the newer type

I see. I bottomed out the nuts when I re-installed my outdrive after the last offseason's repairs as I always have. Is that incorrect? The bushings were replaced a few years ago.

But more importantly, how serious of an issue is it?

 

[Bt Doctur]

loosen the nut and raise and lower the drive again If no more noise remove and lubricate the bushing and retighten
If it still make a crunching noise then suspect a rusting u joint

 

[ratdude747]

loosen the nut and raise and lower the drive again If no more noise remove and lubricate the bushing and retighten
If it still make a crunching noise then suspect a rusting u joint

Will check.

The U joint was somewhat rusty but smooth when I greased it this offseason.

 

[Bondo]

Ayuh,...... 'bout the only other thing that could make that noise could be very dry dragging hinge pins,.....

 

[ratdude747]

No change after loosening bushings.

 

[Candy Gramformongo]

Try divide and conquer. Undo the aft end hyd. rod nuts. Raise and lower drive by hand. See if sound is still there or not. If not, extend and retract rods, listening. Eventually the sound source will be located and its seriousness determined.

 

[ratdude747]

Pulled the rams off. Was tight and dry... A couple of year ago I used silicone paste but apparently when I had the drive off last I didn't reapply anything. What's the suggested lube?

As for the noise. I think I found it. The upper case is grinding on the gimbal ring:

View attachment VID_20260705_213753.mp4

I should have remembered. This isnt a new issue. The original upper case also rubbed there:



(Last season, the original case had a gear failure due to rust pitting caused by seal faulures and it was cheaper to swap and reseal another 888 upper case assembly than to shim new gears and bearings)

What if anything should I do here? The old case probably self-clearanced over the years. As far as I know the gimbal ring is intact (steering a tad sloppy but nothing alarming). Sand and polish the faces until no more grinding? Outdrive alignment issue? Or worse?

 

[Fun Times]

Was going to mention with hitting something recently it may have bent the gimbal ring but if it was rubbing that much before and after a replacement then maybe an old hit happened too...
For some visual references, the following few links may help with some measuring and things to check to see if something seems a bit off,

MerCruiser Gimbal Rings - MerCstuff.Com

Bad Gimabal Ring Cores

Gimbal Ring Repair

We will weld the top of the Gimbal Ring in the swivel shaft area and re-machine the square in perfect size and location. All rings are painted and have all new WEAR bushings installed.

www.jrmarine.com

 

[ratdude747]

I'll have to measure and inspect closer. If the one shoe is slightly off, am I good to sand the surfaces to adequate clearance? Getting some serious sticker shock looking at replacement rings... Would be the most expensive repair to date.

 

[Fun Times]

I'll have to measure and inspect closer. If the one shoe is slightly off, am I good to sand the surfaces to adequate clearance? Getting some serious sticker shock looking at replacement rings (the one place only has alpha and bravo exchanges, nothing as old as mine... If I needed to go there maybe they'd refurbish without an exchange?)

Possibly...Call them and if possible, try to talk to Ron the owner as according to a friend not long ago (a week ago), he was able to talk to the owner Ron and was guided along nicely with his questions.

 

[ratdude747]

I just remembered another thing... One of the two gearcase ears had arc pitting from a ground clamp when a tool shop and I had tried and failed to weld nuts on broken bolts seized in the case (in both cases we had to drill and helicoil). I thought I filed that smooth but it's possible in the rush to get the boat back on the water I failed. I don't think that's the entire issue, but something I figured was worth mentioning.

 

[ratdude747]

Did some work on it after work today (at least until the heat got to me )

First, the ground clamp damage is on the other side which doesn't rub and has about a 1/8" clearance to the gearcase. Speaking of clerances, that side is flush at the tilt pin joint, while the side rubbing has a small (1/16" ?) gap. Weird...

I used a file and a (mostly useless) sanding attachment for my oscillatory saw to smooth the galling. I was able to smooth it out but we're still rubbing. My next move will probably be to use a flap wheel on an angle grinder to take some more off the gimbal ring shoe since it's still got some grooves in it and I don't think I have much to loose since otherwise, I'm looking at a replacement gimbal ring?