Replacing genset exhaust hose

[BruceK]

Looking to replace wire reinforced genset muffler > outlet 2" exhaust hose, about 6-7ft in length.
Initial skirmishing says getting it off the muffler won`t be easy, I`m thinking heavy box cutter and wire cutters.

The hose has 4 bends,how hard will it be to get the replacement to bend? Should the bends be formed in advance, or as the hose gets fitted,one end secured.

Hose options seem to be more wire reinforced hose,and the newer silicone type. Would silicone hose tend to close off at the bends?

 

[Maerin]

How long did the hose you're removing last? Silicone is pretty pricey, and unless you're planning to be on your boat a LONG time, it will probably be a good investment for the benefit of the next owner. <G>



I just had to remove my 5" hose from my main engine exhaust. I used a 4" grinder with a diamond tile cutting wheel to split the hose longitudinally at the ends. It made a bit of a mess, but it was easy to control the depth and the wire acted as a gauge. The hose slid right off. For a smaller genset line, you could probably get it loose enough just with a heat gun. Not a hair dryer, but a heat gun. You don't really need to worry about overheating the hose, you're gonna toss it anyway, so get it soft and it should loosen nicely.

Good luck!

 

[twistedtree]

The wire in the hose is to keep it from collapsing/kinking when bent. Most silicon hose doesn't have that and is only meant for short, straight runs. But I think there are a few versions that can be used for bends and longer runs. You will have to check the specs and recommended applications in the manufacturer's data sheets. For what you describe, I think so-called "hard wall" exhaust hose it the right thing to use. It gets harder as the diameter goes up, but it can be bent to fit.

 

[psneeld]

Looking to replace wire reinforced genset muffler > outlet 2" exhaust hose, about 6-7ft in length.
Initial skirmishing says getting it off the muffler won`t be easy, I`m thinking heavy box cutter and wire cutters.

The hose has 4 bends,how hard will it be to get the replacement to bend? Should the bends be formed in advance, or as the hose gets fitted,one end secured.

Hose options seem to be more wire reinforced hose,and the newer silicone type. Would silicone hose tend to close off at the bends?

https://www.defender.com/product.js...haust-hose&path=-1|2243574|3443701&id=3124777

Trident 252 Series Corrugated Marine Wet Exhaust Hose for longer connections with substantial bends
Thick tube and cover with wire helix between 2 ply reinforcement
Exceptional flexibility and bend radiusResists heat, ozone, exhaust fumes, panting and collapse
Exceeds (SAE J2006-R2, and ABYC & NMMA P-1 exhaust standards)
New Lloyd's Registry Type Approved Cert. 02/00029
Material: Black High Temp EDPM Rubber
Maximum Temp: 280°F (138°C) Max
Colors: Black w/ Blue Stripe

 

[RobertLeatch]

Bruce - we must be doing a similar project. I just bought some 51 mm marine exhaust hose (IRME-051) from Pirtek down on Salisbury road in Hornsby. About $90 a meter. Haven’t installed it yet but seems quite flexible Specs say its bend radius is 180mm and weighs just over 1 kg/Meter. Their online catalogue also has some good reference info in it.

 

[Tator]

Used a Dremel with a cut-off wheel to cut through the wires on our genset exhaust hose. Heat gun was of no help.

Tator

 

[BruceK]

Thanks all,lots of good information.
The hose is old. The muffler may belong to the original Onan MDJE, replaced before my time with an MDKD. There is newer hose from genset to muffler. The old hose, muffler to thru hull, could be original.
On websites silicone hose comes with separate bend sections. So as tt says, not so good for bends.
Whitworths catalogue has a 50mm hose which looks suitable but is rated to 100C( less than the Defender product but if temp >100C I`ve got other problems),it looks similar to the hose from genset>muffler, which is smooth externally, unlike the existing which is corrugated. I`ll try to look at it today at the Drummoyne store,that will also tell me about bend ability.

I have bought from ever helpful Defender before,but hope to access this locally. I will check Pirtek as Robert suggests. I have a Dremel if the heat gun fails, I`m also thinking of hacking into the hose with a Stanley type knife(a heavy box-cutter) and wire cutters, if the heat gun doesn`t loosen it.

 

[psneeld]

You can get the Trident hose on eBay...not sure if international though...

 

[twistedtree]

Thanks all,lots of good information.
The hose is old. The muffler may belong to the original Onan MDJE, replaced before my time with an MDKD. There is newer hose from genset to muffler. The old hose, muffler to thru hull, could be original.
On websites silicone hose comes with separate bend sections. So as tt says, not so good for bends.
Whitworths catalogue has a 50mm hose which looks suitable but is rated to 100C( less than the Defender product but if temp >100C I`ve got other problems),it looks similar to the hose from genset>muffler, which is smooth externally, unlike the existing which is corrugated. I`ll try to look at it today at the Drummoyne store,that will also tell me about bend ability.

I have bought from ever helpful Defender before,but hope to access this locally. I will check Pirtek as Robert suggests. I have a Dremel if the heat gun fails, I`m also thinking of hacking into the hose with a Stanley type knife(a heavy box-cutter) and wire cutters, if the heat gun doesn`t loosen it.

If you want to pursue Silicon hose, Trident 252V is a silicon version of the Trident 252, and can be bent and used over long runs without collapse. I have attached the trident catalog for reference so you can see the different hoses.

 

[BruceK]

Half way there,removed the old hose today. Heat didn`t do much,so the Dremel was put to work. A vertical cut in the hose the length of the pipe it was on soon saw the hose open up permitting removal.
We are going with one length of wire reinforced replacement hose. Silicone would be easier but needs 4 bends, with clamping both ends of the bend inserts. The new hose seems more flexible than the old(could be just age but don`t think so), I will add a couple more "U" holders so it is nicely held before each bend. We will likely need some kind of lube when fitting the hose,that`s already onboard. The old hose used simple hose clamps both ends,replacing them with 2 bolt clamp types. Next weekend we`ll fit the new hose.

 

[BruceK]

Job done,new hose fitted. Much easier refitting than removing, new hose takes bends easily, no need to add the extra hose holders, it sat so well. The bolt type exhaust clamps are way better than the hose clamps they replaced.
I had in mind the guy who replaced the 4" main engine hose on a previous boat, looked as if he`d gone 2 rounds in the boxing ring with a bear. This proved way easier than anticipated, but I guess that`s the unknowns of the first time.