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View Full Version : Uneven exhaust temps


brwn234
08-23-2007, 12:39 PM
I've got a '00 22zx with a completely stock 7.4 MPI. The right/starboard exhaust hose is cracked and beginning to fall apart. The flange where it meets the transom has some brownish marks that look like its burned. The left side looks great, no problems. So I got one of those laser thermometers and the right side is about 148 and the left about 108. I'm thinking my problem is uneven water flow. I tried to have someone ride behind me and look at the flow but they couldnt tell me anything. So I wanted to check my hoses and passages for any blockages or retrictions. What direction does the water travel through the manifolds? Inlets, outlets? Any other ideas, or things for me to check?
MOP
08-23-2007, 02:10 PM
Are the manifolds and elbows original? If so I would drain them out and pull the risers off and inspect them they may be corroded and be past service life!

Phil
brwn234
08-23-2007, 04:40 PM
Everything is original, manifolds and risers. It also has Silent Choice Exhaust. How do I pull the risers off? Do I need to get any gaskets or sealant before I yank em off? What should I be looking for?
MOP
08-23-2007, 07:34 PM
If the boat has been run in salt I doubt you can save the manifolds and risers, 7 years is a long time even in fresh water there would not be much life left in them. Anyway the risers are the part where the large exhaust hoses attach to, if you are 1/2 way mechanically inclined just take a minute and look them over they are a very easy thing to do. Depends on how much metal is left whether or not they can be saved.

Phil
brwn234
08-23-2007, 07:44 PM
Never been in saltwater. I can handle the mechanical part, no prob. I'm just wondering if there is a gasket or anything in there. Also what am I looking for? Is there just a main exhaust channel and then water jackets on the outside? Can I clean them out if they're clogged or are they just done by that point?
RedDog
08-23-2007, 08:28 PM
I thought I had read on here before that it is common for one side to run hotter than the other? I know my former 454 OMC and current Merc 502 runs hotter on one side than the other. I don't know how much, but it is noticable when laying your hand on the risers....

148 don't sound so hot?