omc exhaust?

[UFO8MyCow]

I just bought an armada sarenza with a 5.0 OMC cobra and after hydrolocking it last weekend I was looking for possible causes I found that the exhaust hose that goes into the lower unit has holes on the bottom of each of the ribs my dad thought it looked like it was suposed to be like that becouse they are texactly the same in each rib but I thought it was rubbing on somthing but when I lowered it I couldnt find where it would be rubbing. I have looked at the pics online and they dont show the cuts. Does anyone know if this is normal?

By the way does anyone know if this drive is suposed to have a flapper to stop water from getting into the engine and if so where is it? I cant fimd it in the manual.

 

[Gary H NC]

Re: omc exhaust?

Thats the exhaust bellows and yes they do have holes or slits in the bottom for exhaust relief.
The flapper is in the metal Y pipe behind the engine.
I doubt the flapper is the problem unless you took a wave at the stearn or stopped the boat very quickly that caused water to be forced back up the exhaust.Did it have water in the cylinders on both sides?
I would suspect the exhaust manifolds.They can leak internally and dump water back into the cylinders.
Have you looked for water in the oil?

 

[UFO8MyCow]

Re: omc exhaust?

I was idling for a litle while before I shut it down and the next time I tried to start it it was hydrolocked.there was some water in the oil but I figured it was becouse of he hydrolocking. Is it the manifolds themselves that go bad or just the gaskets?

 

[Bondo]

Re: omc exhaust?

Is it the manifolds themselves that go bad or just the gaskets?

It could be the Manifold has Rotted thru,.....
Or,...
Where the Manifold,+ Riser meet, they Rot so bad, that a Gasket won't hold.......

It's Rarely Just a Gasket.........

 

[UFO8MyCow]

Re: omc exhaust?

this may be a stupid question but what is a riser? #35?

 

[olbuddyjack]

Re: omc exhaust?

The riser elevates the exaust above the water line so water doesn't flow back up the exaust into the engine. It also provides an exit for the cooling system water. In your system the water from the manifolds flow up into the risers and exit with the exaust gases at the rubber coupler to the "Y" pipe.

I think Gary and Bondo are steer'n you down the right road. Good luck checking them out

 

[Gary H NC]

Re: omc exhaust?

Yes #35 is the riser..

 

[Bondo]

Re: omc exhaust?

Ayuh,........

Look for Errosion,+ Deterioration on/ of the surfaces between pt# 35,+ 45........

 

[UFO8MyCow]

Re: omc exhaust?

If they are bad would I have to replace them or could they just be refinished?