"probably" a lower unit failure...

LivinnSadley · **Joined:** Tue May 29, 2012 12:47 pm **Posts:** 38

Good Morning All,

On my way back to the launch yesterday evening on the CT River I experienced an issue.

To the best of my memory because it happened so quick, as I was cruising slightly over 30mph I heard a small thud that was followed by a quick deceleration.
I immediately cut the throttle back to neutral and leaned over the back of the boat to listen.
The motor sounded fine but heard some odd noise from the lower unit so I cut the engine.
After giving everything the once over everything looked fine from the outside.
I tried to turn over the motor with no luck (I think a separate issue (starter and/or alternator on its way out))
I was towed in by my father's pontoon and we took it home.
With the boat on the trailer I could see signs that I may have hit something with the prop (a very small gouge in paint in the same spot in each of the 3 blades).
After starting boat in the driveway and finding out the motor sounded fine we tried to put it in gear with no luck. The boat would shake a lil then rev with no spinning of the prop.
My father and I pulled the lower unit to try and diagnose the problem and found the gimbal bearing housing full of water. There was a little rust but it does not seem to have been the immediate source of the problem but will be replaced. The bellows are only 2-3 years old and seem to be in good shape. Everything beyond the gimbal bearing inside looks fine, all splines are in good shape, universals are working properly.

So after all that, here is my question: With the lower unit off, If you move the shifting lever inside the lower unit up or down into forward or reverse, should you be able to spin the prop by hand? I can spin the blade in either direction without the drive shaft and universals spinning.

If this is bad, what does this usually mean? What has been damaged? I have yet to disconnect the upper drive from the lower drive.

This is my first experience with any lower unit issues so I am trying learn as I go. Any info or possible diagnosis would be a great help.

P.S. 1993 Sundowner 215 5.0 EFI with a Cobra Drive and a 3-blade aluminum prop

Thank you in advance,

ric · **Posted:** Mon Jun 08, 2015 8:17 am

Well, having water in the gimble bearing area is a horrible. Pretty much one of the worst things that can happen. Did you check the drive oil for milkshake?

LivinnSadley · **Joined:** Tue May 29, 2012 12:47 pm **Posts:** 38

I am afraid to say that we changed out the gear oil the day before but I did not check the oil after the incident.

I'm sure we did it correctly but now am obviously second guessing myself.

I think the water in the gimbal bearing housing may have been a result of the issue and not the reason for it but idk.

We were in a hurry pulling the drive off in the dark and sort of gave up for the night.

I am now searching for leads to check before I get out of work and can get back to the boat.

GottWhat · **Posted:** Mon Jun 08, 2015 8:35 am

That really sucks.

Definitely check to see how the gear oil looks. If it is milkshake-ish that means water has made its way inside. Also, look for shavings. If you had a major failure, I would imagine there would be quite a bit of evidence.

babbot1 · **Joined:** Tue Mar 12, 2013 3:46 pm **Posts:** 570

If you are lucky you only have a spun prop hub and need the prop fixed or replaced, plus your gimbel. Pull the prop.

We are on the CT river as well and the submerged debris is very annoying and all over the place. I came within yards of hitting a floating log the size of a tree the first trip when we got our boat. I had a spotter help me look out and it was a good thing. When its choppy its hard to see debris.

ric · **Posted:** Mon Jun 08, 2015 9:19 am

You filled from the bottom and pumped it up right?

rpengr · **Posted:** Mon Jun 08, 2015 9:30 am

That sounds pretty bad, but if the housing is not broken, then it's all fixable.

If the unit is in forward or reverse, then turning the prop should turn the input shaft also. If the prop is spinning freely then something is broken...most likely a shaft. Broken gear teeth will usually try to catch or grind, so it doesn't sound like that. Only other thing is the cone clutch, but I don't know much about what (if anything) can go wrong with the cone clutch.

I would start by draining the oil, then removing the top plate from the upper housing (be careful to keep track of any shims). Your problem might be evident right at the top.

LivinnSadley · **Joined:** Tue May 29, 2012 12:47 pm **Posts:** 38

Yes, we did pump the gear oil from the bottom up. My father has done this many times on his boats for over 20 years.

With the lower unit off and turning the prop by hand it really does not make any sound, it just spins freely.
When turning the input shaft by hand it sounds more "rubbery" and is difficult to spin and again the prop doesn't turn.

This leads me to believe the issue is in the lower unit and not upstream in the housing.

I also want to reiterate there was a minor thump and very very minor dings in the paint on the prop blades.

I will be pulling the upper from the lower this evening when I get out of work to check it out.

Any other thoughts?

Just to add, before the incident, the boat started fine, trimmed fine, shifted fine, and sounded fine. There was no precursor to the incident. If there was no small dings in the paint on the blades I would not even have thought I had hit something.

Jsyphil · **Posted:** Mon Jun 08, 2015 9:54 am

As above, drain the oil, or at least have a look at it. I had an old Chrysler outboard on a 16' speedboat a good few years ago that shredded the gearbox. Came to a swift halt from 40kts to nothing and the engine still screaming.
I drained the oil and it looked like when you open a tin of silver paint, so if something's gone badly wrong, you should see.
Like others have said it may be the bushing on the prop (Hopefully)!. Pull the prop and look at the splines and rubber bush.

Otherwise, you'll just have to split them like you say and start investigating. Good luck....

ric · **Posted:** Mon Jun 08, 2015 9:55 am

Maybe you just busted a prop hub, but you luckily caught the leaky bellow. I'd change that gimble bearing and u-joint out.

GottWhat · **Posted:** Mon Jun 08, 2015 10:03 am

If your lower unit is trashed, at least replacements are available and not that expensive relatively speaking: http://www.sterndrive.cc/product/Fits-O ... 85586.html

LouC · **Posted:** Mon Jun 08, 2015 10:59 am

First: is this the standard dog clutch Cobra, or the cone clutch?
I looked around on the Crowley Marine website and found out the following:
If your model number starts with a 584, the 58=5.8 and the 4=4bbl carb, those models had the dog clutch.
If your model number starts with a 58FA or FB those had fuel injection and they had the cone clutch.

http://www.crowleymarine.com/1/OMC-Stern-Drive/1993.cfm

If it's the cone clutch I know nothing about those; but if it's the dog clutch model then read the following:

If you shift the drive manually with the shift rod it should lock into both fwd and rev, neutral is in the center.
When you changed the gear oil how much did you get in? Most Cobras take ~ 64 oz of gear oil, the ones for the 3.0 and 2.3 might take a bit less, but the regular V6/V8 gear cases take 64 oz or 2 qts.
The bottom most plug is the drain. The next one up next to the joint for the lower and upper gear cases is the fill plug. I pull out the dipstick in the top cover and remove both the drain and fill plugs. Then let it drain for a while. Next with new fiber washer gaskets replace the bottom most drain plug. Next set the dip stick in the hole in the top cover but do not tighten it yet. This allows air to escape so you can get all the fluid in. Now hook up the gear oil pump and slowly pump in fluid till the dipstick reads full. Then screw in the dipstick. Remove your pump from the fill hole and quickly install the fill plug. Last go up top and unscrew the dipstick and let it sit in the hole. This equalizes pressure in the drive and lets air out. Check it again and if it's a bit low you can add some through the top hole; tighten the dipstick.
That's the official OMC procedure right from the shop manual. When they are under filled it wipes out the upper gears first. You can see this if you remove the top cover.
You said you filled from the bottom; if you did that and didn't leave the next plug out till gear oil came out; and then filled it from there, it probably trapped an air bubble and was underfilled. Some people do it that way but that's not what OMC had in all their manuals
If you had water in the bellows you can get water in the gear oil but I doubt that would cause a major failure unless it was like that a long time.

http://www.crowleymarine.com/sterndrives/omc.html
BTW Crowley Marine in Colorado sells rebuilt Cobra drives (dog clutch) but they aren't cheap....

LivinnSadley · **Joined:** Tue May 29, 2012 12:47 pm **Posts:** 38

I dropped the boat and lower unit off to my mechanic last night and his best-guess without ripping the upper from the lower is a busted vertical drive shaft.

I'm traveling to S.C. for work and hope the boat will be back in one working piece by Friday when I get back...

Sounds too easy right? We will see.

New Gimbal Bearing, bellow, and whatever is broke in the lower unit.

Updates to come.

LouC · **Posted:** Tue Jun 09, 2015 3:46 pm

[quote="LivinnSadley"]

So after all that, here is my question: With the lower unit off, If you move the shifting lever inside the lower unit up or down into forward or reverse, should you be able to spin the prop by hand? I can spin the blade in either direction without the drive shaft and universals spinning.

When you said this :if you move the shift lever inside the lower unit....it made me thing you had a standard dog clutch Cobra, because that model has the shift rod in the lower gearcase (it sticks up in the open space in the front of the upper gearcase). The cone clutch shifts in the upper gear housing. They are completely different including the transom mount. The information I found looking around indicated that the FI models had the King Cobra cone clutch drive, the carb'd ones had the standard dog clutch. Only reason why I mention all this is the standard model is much easier to get parts for.

If the shift rod looks like parts 37-40 you have a standard Cobra
http://www.crowleymarine.com/johnson-ev ... mdl=QTSAKX

If on the other hand it looks like this:

http://www.crowleymarine.com/johnson-ev ... mdl=KNBMDU

http://www.crowleymarine.com/johnson-ev ... mdl=KNBMDU

then you have the rare cone clutch King Cobra....

LivinnSadley · **Joined:** Tue May 29, 2012 12:47 pm **Posts:** 38

Unfortunately it seems the whole outdrive is shot.

An improper changing of gear oil (by yours truly) has turned into an expensive lesson learned.

My mechanic sent me a pic showing all the upper gears bone dry and grinded down to nothing.

Is it true that if this happens to the top the bottom is useless?

Oi vey, so where's the best place to find a replacement?

www.iFourWinns.com

"probably" a lower unit failure...

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