Help with exhaust hose replacement

[pimerese]

I need to replace the loop of exhaust hose in my 1985 Hunter 31. This is the loop in the aft rope locker that looks like an upside down U. It leaks water at the top of the loop whenever the engine runs. My questions are;​

1. Can this safely be done while the boat is in the water? How much water egress should I expect?
2. The old hose is marked Shields 2”. I assume that is 2” ID. Correct?
3. Any tips for removing the old hose from the molded flanges?
4. Wouldn’t it have been better to have a smaller 180 degree fiberglass bend with straight hoses coupled to it rather than make the bend with the hose?​

 

[Ed Schenck]

Is the hose leaking or do you have an anti-siphon valve that is leaking? My boat has a straight muffler with the big loop and no siphon. The exhaust is above water so I can work on any piece of it at any time. I think you can do the same. Replace the hose or spend the money for a good waterlift muffler.

 

[pimerese]

Ed, AFAIK it is the hose leaking. I didnt see an anti siphon valve, just a loop measuring about 55 inches end to end, but i'll be sure to recheck. My exhaust line exits the boat right at the water line, possibly just barely above it. I think all the flanges I am looking at are above, so I think its safe too. I just know itll take some time to free up the old hose and wanted to be sure there wouldant be a lot of water egress.

 

[Steve Dion]

The hose at the mixing elbow basically gets cooked onto the metal.

When I did mine many years ago I used WD40 and some screw drivers to seperate the hose from the elbow. It is a very difficult job to replace the entire hose on the H'31. I would suggest that you get some electricans lube (the use it for running wires in conduit) to lube the hose. The muffler in molded into the boat and the fitting is above the waterline, so there should not be any issue with water coming in the boat.

You may also want to r/r the mixing elbow while you are at it because you do not want to do this again too soon.

 

[Sanfelice]

Tight hose

If the ID is tight you can get a pipe expander from an auto store. Some stores lend them out. This really helps with sanitation hose but can also work with exhaust.

 

[redhead78]

To keep out water, start the engine, close the raw intake, maybe 30 seconds shut down the engine. There will be minimal water in the system. Keep a small and 5 gal bucket handy to catch any lingering water. Red

 

[amcmahon]

Please be extreamely careful at the muffler end. The muffler gets very brittle and will crack if not careful - I know , I broke mine when I changed the hose and used a screw driver to seperate hose from muffler. just carefully cut it off. Nightmare to replace muffler!