2005 Merc 8.1 Horizon's with aluminum exhaust manafolds

D

dbach

New Member
Nov 20, 2009
2
Hilton Head Island, SC
Boat Info
340 Sundancer 2005
Engines
Horizon 8.1
2005 Merc 8.1 Horizon's with aluminum exhaust manifolds

I have a 2005 340 Sundancer. I just discovered salt water intrusion from a hole in the aluminum exhaust manifolds. New versions of this engine comes with cast iron manifolds. I did not expect this to happen after 4+ years. Has anybody had this problem? Will Sea Ray, Mercruiser or extended warranty help?
 
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Yes. Search my name and aluminum under advanced search. Use your SR dealer as your advocate. It has been a long time, though. '05's are 5 years old. The corrosion warranty is only 2 or 3 years. Do you have heavy damage?

I bribed my dealer. I promised to buy another extended warranty out to the 7 year mark if he got Merc to replace the manifolds. We both did it.

EVERYONE With these motors needs to know about this!

EDIT: http://clubsearay.com/forum/showthread.php?t=6038&highlight=aluminum
 
Hampton had his replaced by his MM dealer (jump in here John if I'm wrong), and on John's advice, I had mine replaced as a condition of my purchase agreement with MM.

Mercruiser picked up the tab on mine for parts, I paid labor (my boat was an '05 that I purchased from MM in Dec '08). It appears Mercruiser evaluates these on a case-by-case basis, so check with your dealer would be my advice.
 
My boat was salt for 5 seasons before we purchased it and brought it to the Lakes. What are your opinions on replacing the elbows? I understand that they are stainless. I have purchased the manifolds and all the gaskets. Also bought a few small items like o-ring gaskets for sensors and some 8mm all-thread to help with installation. I was going to wait to see what the elbows looked like before spending another 2 grand. Thoughts?
Thanks
 
Don't forget about insurance as well. They may cover it if the warranty does not. Know someone going through replacing his engines not under warranty but insurance MAY cover some of the repair bill.
 
Just for the record, John's dealer is an independant dealer, not Marine Max.

This is a known problem with the earlier 8.1's, one any Mercruiser dealer should be able to help you with, however, due to the numbers of 8.1's sold by Sea Ray dealers, your SR dealer likely has more leverege with Mercruiser.
 
I thank everybody for their help. I did use my Sea Ray dealer to be my advocate. They documented the damage (extensive) and got some help with parts from Mercruiser.

What I learned is that if you own early 8.1's AND you operate in salt water, you should replace your exhaust manifolds with cast iron or powder coated cast iron manafolds BEFORE you have to replace engines!

thanks, David
 
dbach said:
I thank everybody for their help. I did use my Sea Ray dealer to be my advocate. They documented the damage (extensive) and got some help with parts from Mercruiser.

What I learned is that if you own early 8.1's AND you operate in salt water, you should replace your exhaust manifolds with cast iron or powder coated cast iron manafolds BEFORE you have to replace engines!

thanks, David
Click to expand...

Do we know what years we are talking about? I'm hoping that mine has the cast iron or powder coated, but need to take a closer look this weekend.

Kevin
 
BadaBingII said:
Are people having issues with fresh water boats ? I am on Lake Michigan.

Thanks
Click to expand...

There are other posts on this subject. Bought my boat from Florida and decided to change all 4 manifolds since one had a pinhole leak on the outside. Didn't know that cast were available so used OEM aluminum.

Once aware of the concern (after I replaced of course), another CSR member who docks in fresh water, but boats in salt had his 4yr old manifolds replaced under warranty as a precaution. According to him, the existing manifolds were inspected and "looked brand new" - but since the new cast ones were free, he replaced them.

Based on this, it would appear that in fresh water there isn't the same degree of concern about corrosion. Actually, I've seen some major corrosion on cast manifolds here in Lake Huron's fresh water. :grin:
 
I have a 2003 with 8.1's. When I bought my boat 2 years ago, the survey showed that the manifolds needed to be replaced. They were aluminum. They were replaced with Cast Iron. They extended warranty covered the cost of parts and I made the existing owner pay the services as a condition of purchase.
 
Merc paid for mine last yr with the help of my Marine Max dealer. I was very surprised they stepped up on a 5 yr old boat!!

Boughtabouy, your fine. IIRC, they started using cast iron in '06.
 
Just finished up replacing the exhaust manifolds on my 8.1s. 240 hours on the boat (almost 1/2 in salt water) and from what I could see of the inside of the aluminum manifolds (about 3 square inches) they still looked pretty good. Pretty much black coating of some type everywhere I could see.
I bought the iron mercruiser parts for $1600. and after looking at the old ones for 10 seconds my mechanic took them off my hands for $400. plus he used his cool electronic torque wrench to finish tightening everything correctly, greased the hatch lifters and gave me a can of Mercruiser black spray paint.
I still am not sure whether or not I got a good deal or I over reacted. I guess that they would have had to be done a year or two from now anyway and the peace of mind that I get from not having to worry about it anymore was worth the $1200. and the time it took me to do it.
One thing is certain though, there is no super double secret Mercruiser 8.1 aluminum manifold recall.
BTW, thanks to everyone that posted here for the heads up.
 
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I changed the manifolds on the engines this weekend, the weather was poor, so it was a good time to do it. They were original aluminum, and were in salt for 5 years, but had very low hours,
On these 8.1's, it is a fairly straight forward job, and the difficulty is more than likely proportionate to the size of the ER. There was good access on my boat for 3 of the 4, the starboard engine outside manifold was a little tight, as the fuel tank and genny is close by.
Here are a few pics with some comments about a couple of things that may be of help.


I had no trouble removing all the bolts from the motors, and studs and fittings from the manifolds.I didn't see any need to buy any extra hardware. I did have a problem with the temperature sensors. More on that below.


IMG_1507.jpg



when the manifolds are off, do other things that may need doing to take advantage of the access. I changed plugs, touched up paint, and switched out the in-line fuel filts that mount to the frame.
IMG_1502.jpg



When you buy the parts, I recommend getting the manifold temperature sensors, 3 of the 4 broke off when trying to remove them from the manifolds. (they are plastic) The sensor can be seen in the pic below (with the blue electrical connector)
IMG_1510.jpg


The original turbulators were placed between two elbow gaskets. The new turbulators, #8M200433, have the gasket material manufactured onto them. If you want to replace the turbulators, just buy the turbulators, if you want to use the old ones over, you will need two gaskets for each one. I replaced the turbulators on my project.
IMG_1512.jpg


The bottom fittings for the cooling water and drain hoses can be disassembled for cleaning, I used a plumbers tubing wire brush to get this lime and sediment build up out. Be carefull not to loose the check ball
IMG_1508.jpg



If you elect not to replace the elbows, inspect them well around the welds. I decided that they looked good and did not replace them. They are made using stainless steel, so they did not show any corrosion like the manifolds did.
IMG_1514.jpg


I purchased manifolds, temperature sensors, manifold gaskets, and turbulators. Be sure to use some all-thread (8m) or bolts with the heads cut off to help mount the manifolds. They are heavy, and they make life much easier.
Hope this helps someone with their project.


As an edit, here is a photo of the bottom fitting port. This is where the hose fitting threads into the bottom center of the manifolds. I am showing this to point out where there was the most critical amount of corrosion on my manifolds. It was at it's worse just above the threads (manifold is upside down in this shot) on the outside of the manifolds. You can clearly see how much material has corroded away. I imagine that that location provides for the dissimilar metals of the fitting, and the manifold to corrode, and a "shelf" for salt or sediment to settle onto the top of the fitting end. All four manifolds showed the most corrosion in this area. Two of them were paper thin. It may be worth the effort to pull those fittings, if anyone is considering investigating the condition of their manifolds(freshwater). If you are in salt and still have aluminum manifolds, just change them.
Boating2010002.jpg
 
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Great photo, Mark. Thanks for sharing your experience.
 
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