Starboard side exhaust water flow severely restricted

[dbm_nj]

I have a 1998 Baja with a 5.0liter V8 and Alpha drive - The Starboard side "thru the hull" exhaust water flow is severely restricted to the point that the header got hot enough to melt some wiring harnesses & exhaust components and I had to be towed home. Where should I look to find the blockage?

 

[Bt Doctur]

guess the exaust riser would be a good place to start

 

[dbm_nj]

Not sure what you mean - what is an exhaust riser? Where do I look to find it? Is it part of the exhaust manifold?

 

[MarkSee]

On top of the exhaust manifold; something like item #9 in this picture:
https://www.perfprotech.com/mercury...nd-exhaust-elbow/assembly/2697/100?model=1045

Mark

 

[dbm_nj]

Thanks, I will look into that. I am also thinking that the thermostat housing could be blocked on the starboard side - my heat exchanger recently failed and debris may have collected in this. Any other ideas would be appreciated.

 

[Bondo]

Thanks, I will look into that. I am also thinking that the thermostat housing could be blocked on the starboard side - my heat exchanger recently failed and debris may have collected in this. Any other ideas would be appreciated.

Ayuh,..... You didn't mention you got closed coolin',....

What else has been to done both sides of the coolin' system,..??

 

[Bt Doctur]

with FWC there is no diverter in the Therm housing. its just like a car. Does the system cool the manifolds also, called a full system or just the block, half system

 

[dbm_nj]

It is a San Juan Engineering "Block Only" cooling system - I guess I made a bad decision by not following their advise to flush the entire system after installing the new heat exchanger. :frusty:

 

[Bt Doctur]

not really, considering the manifolds and risers are salt water cooled, how old are they? a riser will normally get clogged before a manifold.,

 

[dbm_nj]

I am the second owner but I believe they were part of the original build - 1998.

 

[Bt Doctur]

if you have owned it for atleast 4 years ,your overdue for manifold/riser replacements. risers are about 4-5 years, manifolds a bit longer.
If either one fails it will fill the cylinders with water.

 

[dbm_nj]

I am about 1.5 hours from the boat and won't get to it until Thursday - I have become increasingly concerned about water having gotten into the engine because of the way the boat lost power and took on a significant amount of water because the exhaust section melted (pieces from the diverter to the exhaust tip). Water in the oil is the first thing I will look out for.

 

[dbm_nj]

No Title

Good news, I was able to get to my boat a day earlier than I expected - there was no water in the oil so I just need to repair the burnt sections & wires. I also see that the Riser & Manifold are corroded & full of debris. BT Doctur suggested that they be replaced - do you know a source?

 

[Bt Doctur]

IBoats sells them along with others, google it

 

[Bt Doctur]

http://www.iboats.com/Mercruiser-Ex...9980869--session_id.209523728--view_id.270281
http://www.iboats.com/Mercruiser-El...980869--session_id.209523728--view_id.1160427

 

[dbm_nj]

I have a 1998 Mercruiser Model 5.0 Serial Number OL039995 but this combination is not found on either of the links you provided.
What to do?

 

[dbm_nj]

I have a 1998 Mercruiser Model 5.0 and Serial Number OL039995 but this combination finds no results on either link you provided.
What to do??

 

[Bt Doctur]

Service Literature for MERCRUISER 5.0L ALPHA 5.0L ALPHA
PARTS CATALOGS

• 816596 98 - 5.0L/5.7L ALPHA/BRAVO GEN+

 

[Bt Doctur]

1

860246A10

2

MANIFOLD ASSEMBLY, Exhaust 9 807988A 2 2 ELBOW ASSEMBLY, Exhaust

 

[Bt Doctur]

http://www.iboats.com/Exhaust-Manif...039995 --session_id.673520255--view_id.222132