Omc 1989 Cobra Leg Noise

[beanhauler]

I have noticed that there is a small noise coming from the sterndrive when the stern drive is tilted.Its a rotating noise like a bearing at the point where the drive shaft enters the top of the upper housing.
If i lower the sterndrive the noise goes away.
I changed the gimbal bearing a couple of years ago and am wondering if its that time again?I have greased it occasionally.I changed the bellows and seals etc when i did it.Its not a knock like a universal joint knock its more rotary like a dry bearing although the stern drive is full of oil!
Maybe the non direct drive when the stern drive is tilted transmits the gimbal noise? Or is it likely that the problem is the bearing in the upper housing?
This looks like a devil to change and is shimmed etc.Needs pullers and all sorts
Anyone attempted?Can you get the tools anymore?
Looks like the leg is coming off.
Exchange leg better option?

Grateful for any advice

 

[Gary H NC]

Re: Omc 1989 Cobra Leg Noise

How far do you have to raise the drive to hear the noise?
I hope you are not running it in the trailer position..

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

By trailer position i take it you mean well raised.
No just a few degrees from horizontal...maybe 10 max
If you leave it running its quiet but if i blip the throttle then its really noticeable.
Dead horizontal i hear nothing
That why i think maybe its the additional turning angle that either stresses the gimbal or maybe the upper housing sterndrive bearing.

 

[a70eliminator]

Re: Omc 1989 Cobra Leg Noise

Boy that sounds like a u-joint bearing, keep your fingers crossed.

 

[Gary H NC]

Re: Omc 1989 Cobra Leg Noise

Time to pull the drive and have a look.

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

Well here is what happened.
Fired it up again and did the test but squirted the gimbal with some grease.
No change with noise sounds like a bag of nails!
Unscrewed oil filler at top of upper housing and a load of emulsified oil came out...suspicious.
Decided to whip off leg and as i released the bolts about 2 pints of oil drained out of the gimbal housing.Looks like emulsified hypoid oil.
Dropped it down on the ground and checked the gimbal bearing.Does not appear to be noisy and turns ok,,,may have to change it for the sheer hell of it.
Checked the exhaust baffle and looked as if it had a lump of metal jammed in it restricting the exhaust exit and water as well i guess...thought it was running hotter than it had done before.The metal looks like a flapper with bits of rubber on it.
How critical are these flappers and do they need to be in place and if so can u fit them without removing the engine?Where the devil can you buy them from?
Anyway i digress onto the problem....
Removed lower drive drain plug and checked oil in that.It also appears a bit emulsified but the upper and lower chambers are not shared methinks.Does this mean the lower housing is leaking around the prop shaft..
Removed water pump...no oil in that..removed top cover and drained oil...bearings appear ok not noisy when rotated by hand and no obvious play.

So the question is where did all the oil come from that was in the gimbal bellows?It must have come from the upper housing bearing seal.
But what had pushed the water in there.Did the obstruction in the exhaust baffle put the water pump presure up which forced it way past the seals and into the gimbal area?

looks like thiis lining up to be expensive as repairing the unit requires specialist tools etc
Not sure which way to go now

 

[bruceb58]

Re: Omc 1989 Cobra Leg Noise

The exhaust has nothing to do with the oil in your drive bellows. The oil leaked out the drive shaft seal. You need to pressure test your drive to see what else may be leaking besides that seal.

 

[BLC]

Re: Omc 1989 Cobra Leg Noise

Removed lower drive drain plug and checked oil in that.It also appears a bit emulsified but the upper and lower chambers are not shared methinks

.


If it's the same 89 cobra leg as mine they are shared. I'm replacing the top gear set as we speak.

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

how difficult is that job
I've just read the manual and besides the puller which could be sourced ok you need some special tools.
Measuring aid for bearing pre-load ...to select correct shims and the tools to undo the special nuts on the drive shaft plus the pinion retaining thread screw
Where on earth can you get those!
Also the small bearing on the water pump end needs pulling with a special piece of pipe to avoid damaging the impeller shaft.

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

I think the seal is behind the u joint which is behind the input shaft main bearing
So you have to remove the input shaft main bearing to access the seal.
But water must have got into the upper housing by some method [it can not get in through the gimbal housing as they are new bellows]so either through the lower pinion seal or waterpump seal.
Also the lower unit has very emulsified looking oil in it so it might be leaking there too.
I think a complete rebuild is required with all new seals.

there i also that mysterious piece of metal in the exhaust bellows
looks like a flapper plate maybe?

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

It definitely is a flapper plate so that needs replacing.
Unfotunately its engine out in order to get to the y bracket...Doh.

 

[beanhauler]

Re: Omc 1989 Cobra Leg Noise

Looks like its not the engine out.
Removed the manifolds from both sides and undid the numerous stainless steel bands.Pushed the lower rubber down and managed to wrestle the rubbers from the exhaust.
Sure enough the flapper is missing from the top of the pipe on both sides.I originally thought that flapper was in the junction but it appears not so which is good news.
The leg is off so set about splitting the upper and lower case.Bolts came out ok but the seal needed about a half hour of wriggling to get it to let go.
Removed input shaft and water pump assy.
Think its off to the workshop to get them to install new seals and look at the lower drive/dog clutch assy.
Looks as if its going to be expensive.

 

[howlnmad]

Re: Omc 1989 Cobra Leg Noise

Honestly, unless you have all the tools, a shop area set up for it, and the expertice to do it, your MUCH better off having a qualified tech do it.

Now with that said, I doubt you need to. All you really need to do is replace the seal on the input shaft (thats how the oil got in the bellows) which does not require tearing the drive apart. Should just be a snap ring to remove and then pull the seal out.

I've got an 89 cobra on my bayliner and the drive seal went out on the 4th. You will have to pull the outdrive and then pull the upper driveshaft and it will need to be pressed apart and back together. It 's a good time to change bearings too. I got shopping on line and found both bearings for around 100 bucks, took it apart and went to NAPA. both upper bearings for under 30. There are special tools needed to reassemble tho. Maybe you have a friend with a marine repair shop. Good luck with all of it.