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Old 11-01-2008, 09:30 PM   #7
Chris Foster
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City: Anacortes, WA
Country: USA
Vessel Name: Juz-B-Cuz
Vessel Model: 38' Rawson Trawler
Join Date: Oct 2007
Posts: 278
RE: Replacing exhaust hose

The hose pick was a really good call.* The local NAPA store had one for a whopping $4.95 that I abused the s__t out of until it finally gave up.* It had the pick end bent into kind of a square "U", so it wouldn't go as far between the hose & fitting, but gave a good tool for pulling the hose.

(Warning:* rest of this post contains a lot of whining)*

As to the job itself, well, my lifelong fantasies of becoming a professional marine exhaust maintenance person have been dashed.* Even with the tool, I still had to hacksaw through pretty much all of the hose to get it to release (it had about 6" of overlap on either end.* The old hose must have been in there for quite a while - it was 4" corrugated, and pretty much disintegrated in the area of the tightest bend when I pulled it out.* Access to the line was via "assuming the position" of crawling around the outboard side of the stb'd engine.

Since I had to move the boat on Friday (yesterday), I made certain that North Harbor Diesel had 4" exhaust line in stock.* No problem, they said.* So I pulled the old line out and went to get 3 feet of new.* Oh, we don't stock corrugated line.* Ooops.

Since I had to make a 90 degree bend in less than 3 feet of line, using standard exhaust line alone was out of the question.* So I bought a fiberglass 90 plus 3 feet of the standard stuff.

The problem now was that, while everything would fit beautifully once in place, there was too much misalignment to get everything to start.* Slashed the heck out of my hands trying to muscle it into place as my hand would inevitably slip and rip across the (sharp) wire at the end of the hose.

The silicon sealant was a also good call as there's no way that I could have slipped the line over the ends without it as a lubricant.* Unfortunately, within 10-15 minutes, it would start to cure to the point that things wouldn't move at all.* So during the 3 or 4 different attempts at trying to get it to go together, I had to pull everything apart a few times and scrape the curing sealant off.* I'm wondering if something like Dow/Corning # 4 (DC-4) wouldn't work better - it's basically a high temp silicon grease that doesn't hurt rubber, neoprene, silicon rubber, etc.

The final solution was to reduce the amount of hose overlap on the water/exhaust injector (don't know what to call it - it's not a "riser" as the turbo outlet is well above the waterline - this is just about 10" long, bolts to the turbo on one end, has a water hose coming in on the side, and has the exhaust hose on the other end).* You can overlap the exhaust hose by over six inches, but the bead is at the* very end of the fitting... so I decided that about 3" of overlap would be adequate (allows two clamps above the bead).* My final trick was to put one piece of hose all the way up the injector, then install the other piece of hose and the fiberglass elbow, and then slide about 3" of hose down the injector over the elbow.

The installation saga ended about 3 hours after it started.* But it doesn't leak water or exhaust.* And I managed to get moved to my new slip yesterday morning before the wind picked up!!
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