Engine Exhaust


Philippe, (masiee@worldnet.att.net)

I believe I had the same "iron box" wet muffler system on my Pathfinder that you describe. It mounted on top of the Hurth transmission. See bottom of three pictures shown below.

It finally rusted through and I could no longer epoxy it. I had a new stainless steel pipe constructed using same bolt-on flange to heat exchanger. See first and second photos.

Pipe is asbestos wrapped and inverted U shape. Stainless steel bracket from transmission secures it. Stainless steel fabrication above hose clamps is water mixing chamber with blue hose exhaust water injected into chamber. I specified two inch exhaust to ensure minimal back pressure and provide margin should I have to repower.

Black exhaust hose goes to wet exhaust on platform I built above shaft. It holds Vernalift (#150026), side in, top out wet exhaust. Again, largest that would fit. I replaced thru hull to handle two inch. I'm very happy with system.

Only suggestion: I would reroute exhaust higher on quarter or relocate to transom. The exhaust is often below water level when under higher RPM. Don't think this is good - again back pressure. However, I probably will never change it.

I've suspended Superstor 6 gallon water heater above Vernalift. Just fits.

Just got back from three days at Catalina Island. Smooth seas and great long weekend. I noted max RPM at 3800, 215 degrees exhaust temp, 7.5 kts on a 13R10 3 bladed prop. Normal cruising speed is around 6.5 kts at 3200 RPM. It was a fantastic weekend at the Island - we anchored at Emerald Cove - no other boats all weekend.

Let me know if I can be of any other assistance - hope the pictures attach ok and you can receive them.

Ken Kropf, "Svanen" 1981 #620


Click to enlarge.

From: Henry Neil
Sent: Monday, October 14, 2002 7:54 AM

I have a metal box above my engine which I am told is part of the muffler system. It has an intake and an outflow for water and is rusted to the point where water is coming out of the lower joint at far too fast a rate for comfort.

Does anyone know where I can get a replacement for this unit. I would prefer fiberglass but will take whatever I can get.

Many Thanks for any help from the membership.

Henry Neil (Admiral oif the Texas Fleet)

Hi Dennis & Henry,

I have recently replaced the "metal box" mufflet in my I36/Perkins 4-107. I got a fibarglass Naqualift one from Svendsens Boatyard in Alameda (http://www.svendsens.com). It's roughly 10"x10" with 2" IN and 2" OUT. This unit is bigger than original one so I had to change it's mounting.

Also, my I36 exhaust is 1.5" so I have gotten some fiberglass adaptors and 2" rubber exhaust pipe. In the future I will replace all pipes with 2". Note that manufacturers of there mufflers specify at least 2.5" for greater than 20HP diesels. I though that 2" is better than original 1.5 anyway (besides there is no space for bigger unit). I am now trying to replace exhaust riser since it is completly rusted out.

There are two manufacturers of fiberglass mufflers:

Also, there are two other shops in BA who carry Centek's muflers one in Alameda and one in South SF (see Centek's dealer page).

I simply decided on Naqualift because it was in stock.

Let me know if you have any more questions.

Michal K michkro@hotmail.com

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