8.1s riser issues

[Partyoffive]

Has anyone heard of riser/elbow internal welds failing on 8.1s leading to water leaking into heads and damaging valves? I’ve heard this story several times and am trying to find out if there is an issue with mercruiser OEM risers? I’m looking at replacing manis and risers but don’t want to have an issue with the OEM parts ? If so, what are good alternatives?

I’ve heard this has been an issue on these motors from early 2000-2012 so far. Anyone have any insights?

Thank you

 

[jmauld]

Haven’t heard this. Just replace them with the factory parts.

 

[Spark600]

The 8.1s in my boat had steel exhaust manifolds with SS elbows, And yes it was the SS elbows that leak at the welded joint.

This happened to my friend's boat and he had to due a valve job from the leak.
The way he found it was he filled up the elbow with water and put it on a paper towel over night, the leak was so small it took over night to show up on the paper towel

After his results I pressure tested all 4 of my SS elbows and they were all good.

 

[KevinC]

Yes these welds may crack. When I did my manifolds I also replaced my elbows since I did not have any idea when they were last done. I was told the problem is that even though these are stainless in saltwater these elbows do not completely drain leaving a little saltwater sitting on the weld joint (you can see where the hose is compared to the base). I am guessing the salt water can affect any imperfection in the weld. This is why I added flush ports and flush each time we run.

-Kevin

 

[KevinC]

Has anyone heard of riser/elbow internal welds failing on 8.1s leading to water leaking into heads and damaging valves? I’ve heard this story several times and am trying to find out if there is an issue with mercruiser OEM risers? I’m looking at replacing manis and risers but don’t want to have an issue with the OEM parts ? If so, what are good alternatives?

I’ve heard this has been an issue on these motors from early 2000-2012 so far. Anyone have any insights?

Thank you

If you replace the manifolds order the kits that include all new sensors, hoses, drains etc. If you are getting the elbows make sure to get the right ones - the 340SDAs used the 2" inch taller ones. Also just go OEM - no real good alternatives.

-Kevin

 

[jmauld]

I have a set of 4 stainless steel risers if someone would like to have them pressure tested and reuse them.

 

[Partyoffive]

Thank you all for the info. Much appreciated.