Is it too late when you smell rubber?

[RICHRICH36]

I own a Mercruiser 3.0 since brand new (of course with the boat that it is in). Approx 10 years old. Only about 200 hours on it.

I was cruising first trip from the ramp this season and something didnt seem and feel right. I suspected the gimbal bearing. I pulled the engine cover and could smell smoke. The rubber mixed with grease smoke. It is either coming from the grease seal burning or the coupler.

The gimbal bearing seized up on the shaft.

I have replaced the bearing, checked alignment, it was actually dead on. I checked the splines. As you can see from the pic, nice flats and squared corners. I will be replacing the bellows also.

My question, once you smell smoke is the coupler done? I never felt like it was slipping and it never felt like I had reduced power.

 

[bondo]

Ayuh,..... If the coupler slips, it's done for,.....

Did ya find rubber dust 'round the coupler,..??

If not, I'd suspect it was something to do with the seized gimbel bearin',....

 

[RICHRICH36]

Ayuh,..... If the coupler slips, it's done for,.....]

I cant really say that the coupler slipped as I never lost power and made it back to the dock just fine but the smoke and burning rubber smell is what concerns me.

From the picture attached, to me, it looks like the heat was concentrated between the bearing and the grease seal. But I could be totally wrong.

 

[bondo]

Ayuh,..... Did you find any rubber dust,..??

 

[RICHRICH36]

Ayuh,..... Did you find any rubber dust,..??

I don’t believe so. Space is limited so I was viewing with borscope but from what I can tell there doesn’t appear to be rubber dust.

 

[RicardoMarine]

At any point in time did your seawater pump fail to provide adequate water?
A seawater pump issue may cause the exhaust to become hot enough to blister the interior of the Elbow-to-down-tube rubber coupler ..... which could lead to a burning rubber smell.

 

[RICHRICH36]

At any point in time did your seawater pump fail to provide adequate water?
A seawater pump issue may cause the exhaust to become hot enough to blister the interior of the Elbow-to-down-tube rubber coupler ..... which could lead to a burning rubber smell.

Good point, I just checked that and there doesnt seem to be any signs of warping, burning etc.

 

[kghost]

Ayuh,..... If the coupler slips, it's done for,.....]

I cant really say that the coupler slipped as I never lost power and made it back to the dock just fine but the smoke and burning rubber smell is what concerns me.

From the picture attached, to me, it looks like the heat was concentrated between the bearing and the grease seal. But I could be totally wrong.

View attachment 17409

The grease seal is simply to keep excess grease from entering the bilge area.........it also will keep water from entering if it gets into the bellows.
I doubt very much the seal is your issue.....



What is the bearing doing on the shaft?

The bearing is suppose to stay in the transom housing.

Lets start there....................

 

[makomark]

.....The gimbal bearing seized up on the shaft....

if the engine was running, then there was a lot of heat being generated....so smelling an odor wouldn't be unusual....

When the coupler fails, its usually the rubber between the splines and the housing that lets go.....and as bondo has pointed out a few times, there's usually a dust trail......

 

[RICHRICH36]

The grease seal is simply to keep excess grease from entering the bilge area.........it also will keep water from entering if it gets into the bellows.
I doubt very much the seal is your issue.....



What is the bearing doing on the shaft?

The bearing is suppose to stay in the transom housing.

Lets start there....................

There was water in the bellows. The washed out bearing got so hot it welded itself to the shaft.