Exhaust Elbows on Mercruiser 6.2 Horizon

M

MichaelNJ

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When do people typically change their exhaust elbows on fresh water cooled engines. The manifolds and risers are FWC but the Elbows are raw water cooled and the raw water exits through them into the exhaust. They are ceramic coated in that year.

My boat has been used for about 9 years. It is docked in the lower Hudson river so it's probably more salt than brackish.

Is there an easy way to check the condition without actually pulling them off? I was thinking of removing the big output hose and using and inspection camera so I have to remove and replace the gaskets.

Anyone using aftermarket elbows? They are a lot less expensive than Mercruiser.
 
I have a '88 merc 3.7L 4 cylinder fresh water cooled. I'm on the fourth elbow. Put one on in 2000, 2007, and last year 2014. Boat is docked in Stony Point. Boat is in the water in Key Largo FL for 3 months in the winter. The salt is heavy there. I change it when the motor starts to run hot and I can't keep my hand on the elbow because it's too hot. I use aftermarket elbows.
 
I did both Exhaust Elbows and Manifolds this year. I found www.sterndrive.com very reasonable. Get them to quote you.
 
I think you are due for a change. Soon. I would go with after market, like Sierra.

You need to pull them to inspect. Your looking to see if the jacket is getting clogged up. I do not think you can see that with an inspection camera. Some people "rod" them out but while that may get the cooling water flowing better, the metal is corroding away at the same time. Should water get in your engine from this, the cost to change them will look like pocket change.

After you change them measure the temp of each with a IR thermometer and keep as baseline.
 
Thanks for the advice.

Pocket, I keep my boat at Stony Point Bay Marina for the Winter. What did your elbows look like after 7 years? Are you using Ceramic coated?

ddurand, are all the aftermarket elbows ceramic coated as well? I agree with you about the water ingestion.
 
The generally quoted preventative maintenance schedule for RW cooled cast exhaust components is 3-5 yrs, which I tend to follow on my blue FWC engines. I have gone a little more and less. It's possible the ceramic-lined ones you have could have extended life to some extent , but George van Parys pointed out long ago the ceramic coatings on something like these cast iron exhaust parts eventually tend to craze due to heat cycle expansion and contraction of the underlying metal, then crevice corrosion takes over.

These parts are not ones to think of in terms of "if it ain't broke, don't fix it" because by the time they are "broke" you may need a new engine.

I use the frequent hand on the top of the riser/elbow check ( should be able to keep it there indefinitely at all rpms if RW flow is sufficient) to judge whether to replace earlier than the above-mentioned schedule. But if flow is still good, that doesn't tell if water passages are getting too thin.

I figure if I am checking condition I might as well replace my elbows, gaskets , blockoff plates and the torque-stretched fastener studs and bolts and lock washers.

If you a still thinking of removing the big exhaust hoses to peek at the elbows keep in mind you must 1st tightly cap the transom exhaust outlets if those hoses are below the water line to prevent potential sinking.
 
MichaelNJ. not sure if you saw my reply about Sterndrives.com, or if it has to be approved before actually being posted..
 
quote:
Originally posted by Sandy

The generally quoted preventative maintenance schedule for RW cooled cast exhaust components is 3-5 yrs, which I tend to follow on my blue FWC engines. I have gone a little more and less. It's possible the ceramic-lined ones you have could have extended life to some extent , but George van Parys pointed out long ago the ceramic coatings on something like these cast iron exhaust parts eventually tend to craze due to heat cycle expansion and contraction of the underlying metal, then crevice corrosion takes over.

These parts are not ones to think of in terms of "if it ain't broke, don't fix it" because by the time they are "broke" you may need a new engine.

I use the frequent hand on the top of the riser/elbow check ( should be able to keep it there indefinitely at all rpms if RW flow is sufficient) to judge whether to replace earlier than the above-mentioned schedule. But if flow is still good, that doesn't tell if water passages are getting too thin.

I figure if I am checking condition I might as well replace my elbows, gaskets , blockoff plates and the torque-stretched fastener studs and bolts and lock washers.

If you a still thinking of removing the big exhaust hoses to peek at the elbows keep in mind you must 1st tightly cap the transom exhaust outlets if those hoses are below the water line to prevent potential sinking.

Plus, my hoses at least are installed such that the elbows have to be lifted off the manifold studs to get that stiff hose removed from the elbows. And still very hard to get them to release their grip on the elbow- twisting the elbow helps after much careful prying.

Click to expand...
 
Thanks Sandy. I totally agree that this is not something that you can wait for to fail.

I did see it Carver.
 
There's a guy at my marina who wishes he'd changed the risers before he ruined both engines. Risers are cheap, engines are not.
 
I am not sure they are doing ceramic coated ones any more. I think it was a point and time and in the end they were not worth the extra cost.
 
I'd be interested in how the ceramic held up in the water as well as the exhaust passages. Pix would be nice.
 
quote:
Originally posted by MichaelNJ

Thanks for the advice.

Pocket, I keep my boat at Stony Point Bay Marina for the Winter. What did your elbows look like after 7 years? Are you using Ceramic coated?

ddurand, are all the aftermarket elbows ceramic coated as well? I agree with you about the water ingestion.

Click to expand...

After 6 or 7 years the elbows are clogged with rust and scale. That's why the motor runs hot. I put my hand on the elbows frequently to check them though I'm good for several years now. I don't think they make ceramic coated elbows for my motor. I am in SPBM in the summer. In 2014 I was 2 miles from the dock when the temperature went up. I shut it down and had Sea Tow bring me in. Cheaper to have Sea Tow than need a motor.
 
Micheal, you have had excellent service from the OEM elbows why buy something else? I'm on my fourth set of manifolds and elbows but looking back I got the best service from the OEM original set. If I still have this boat when it's due for another set I will be buying OEM. Just my two cents.
Rob
 
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