Re-doing my Wet Exhaust

[Finnerty]

The 3" dual wet exhaust on my 26' Tolly has been burning out just after the exhaust manifold. The 3" hose does not come straight off the end of the exhaust elbow like it should but instead tries to make a 30 degree bend, kinks and burns. In order to fix this I'll put in a 45 degree elbow, I'm thinking the rubber Trident-Flex type.

A couple of things I'm wondering: how long should I make the first straight section of hose before the 45? (longer the better I'm sure but it gets in the way...) and should I use the pricier blue Trident-Flex hose (3X the price of the black hose) or is this overkill....link to my sketch: (removed, see update below)

 

[HT32BSX115]

Re: Re-doing my Wet Exhaust

Howdy Dave,


The "wet" exhaust should NEVER "burn out" after the manifold.... (ever).......

If it does, you probably do not have enough water flow thru manifolds and risers.

This can be due to obstructions in the raw water circuit. That could be debris, previous impeller fragments, rust clogged manifolds and/or risers.

The Bravo pump like you probably have flows MORE than enough water to keep from burning up rubber parts in your exhaust system.

Pull and inspect your raw water circuit from the pump to the t-stat, oil cooler (if installed) and to the manifolds.

You'll probably find that something is reducing water flow.....


Regards,


Rick

 

[Bondo]

Re: Re-doing my Wet Exhaust

Howdy Dave,


The "wet" exhaust should NEVER "burn out" after the manifold.... (ever).......

If it does, you probably do not have enough water flow thru manifolds and risers.

This can be due to obstructions in the raw water circuit. That could be debris, previous impeller fragments, rust clogged manifolds and/or risers.

The Bravo pump like you probably have flows MORE than enough water to keep from burning up rubber parts in your exhaust system.

Pull and inspect your raw water circuit from the pump to the t-stat, oil cooler (if installed) and to the manifolds.

You'll probably find that something is reducing water flow.....


Regards,


Rick

Ayuh,... Agreed,... Yer tryin' to treat the Symptoms of the issue, rather than the Cause of the problem....

With that said,...
I'd go with metal fittings, 'n rubber couplers, rather than pre-bent rubber fittings...

 

[Finnerty]

Re: Re-doing my Wet Exhaust

Thanks, following your advice that this is the symptom of a problem I opened up my entire raw water system from: intake, strainer, hoses, pump, gear cooler, oil cooler, heat exchanger, exhaust risers and elbow. All components appeared OEM and in acceptably clean/clear condition with one exception.
The Jabsco raw water pump Model 43210 (that replaces Quicksilver Model 46-72774 A32) was mounted in the bracket with the INLET on top, rather than the OUTLET as specified by the Mercruiser Manual #3 (Note that Inlet and Outlet were plumbed correctly for the engine rotation). The manual says "IMPORTANT: Pump must be positioned correctly or overheating of engine may occur"
We'll see if this makes a difference when I get back out on the water in a few weeks.

 

[Bondo]

Re: Re-doing my Wet Exhaust

Ayuh,... Excellent, it appears you found the Real Issue....

Good Luck...