exhaust riser acceptable temp range?

[Oldnbold]

ive A new to me 2001 23’ sea Ray with a 6.2L , 320HP engine. When I hand test the temp of the risers, I can’t keep my palm on the top for more than a few seconds due to temp. This is much hotter than my ‘95 7.4L riser. Is this model riser supposed to be hotter or should I get right on with a new seawater pump?

 

[Bondo]

Ayuh,..... Normal temps can run up to 170*, which is many degrees hotter than skin can handle,......

If you don't know how old the impeller is,....... Change it,....

 

[Deepwtr]

I have been questioning the same thing on my boat. I realized after the initial panic that without knowing exactly what temp they were, I didn’t really know anything. They will be different temperatures. Get a cheap IR temperature gun and then you can know for sure when run again.

you might have a problem, but then again you may not.

 

[wingless]

Good test and good to be concerned.

My 454 MAG MPI Horizon (7.4L) also permits continuous exhaust holding when all is good.

Assumption is raw water cooled exhaust, so disassembly of the elbow for inspection of the internal raw water passages for corrosion and inspection of the SOLID wall thickness between raw water and exhaust gas is a very good step. This should be performed annually on a salt water boat w/ raw water exhaust cooling. It requires new gaskets for reassembly.

 

[QBhoy]

I think you should be able to hold the top for up to about 7 secs or so (the old fashioned measure). The temp will also vary when in the water and on the hose too.

 

[Oldnbold]

Thx guys, I’ll temp test with a gun and see.
I may flip this boat so if I flip it, no go on the new seawater pump, but I need to make sure I don’t scorch the motor or exhaust rubber during test runs.

Also, does the internals of the risers get corroded like the lower unit? it’s obvious the zinc anodes on the lower unit weren’t enough to stop the pitting in the metal

 

[wingless]

Also, does the internals of the risers get corroded like the lower unit? it’s obvious the zinc anodes on the lower unit weren’t enough to stop the pitting in the metal

No, it corrodes in a totally different fashion.

The lower unit is cast aluminum, the exhaust is cast iron.

Here is an image (not mine) showing raw water passage corrosion and showing the SOLID wall thickness between raw water and exhaust gas passages being compromised.

 

[wingless]

FWIW, I was getting 3-4 years on my salt water cooled exhaust parts, w/ no way to flush and no way to drain, w/ salt water sitting in the expensive cast iron 24/7/365.

At the last replacement I redesigned my exhaust. Now I drain after every usage, then flush w/ fresh water, soapy water, Salt Away, then drain bone dry until the next usage.

My last internal inspection, after three years of usage, reveals the internal of the cast iron parts to still looking brand new.

My expectation is that I am done replacing these parts because of my change.

 

[Scott Danforth]

the 320hp 6.2 with the hyper-complexified single-point drain will also have about half of the hoses plugged with debris after a few years.

the dry-joint manifolds still take out the motor if they leak

if you are in salt water, how old are the manifolds?

 

[Oldnbold]

The boats history is fresh water and manifolds are oem with 480 hrs. 01 sea ray

 

[achris]

The boats history is fresh water and manifolds are oem with 480 hrs. 01 sea ray

That's now 18 years. Even in fresh water, cast iron corrodes. I'd be pulling the elbows (you don't have 'risers') and manifolds and inspecting the water passages.

Chris.........