Exhaust run for 1975 36 MKII

Does anyone know how the exhaust was originally routed on the 36? Did Gulfstar use waterlift mufflers? In particular I'm interested in knowing how the port exhaust was run.

My 4-154s have a 2" diameter elbow with 4" diameter hose connected to them and no waterlift. On the port side the hose runs under the aft head on it's way to the transom creating a low spot under the head where (too much) water collects after the engine shuts down. The hose is crushed in some areas so I want to re-do it, probably with 2". The exhaust is barely at the waterline so getting a downhill run especially through the aft head appears to be difficult if not impossible without waterlifts but I can't figure out where to mount them.

Thought it would be nice to start with the original design but can't find info on that.

Sounds like a problem in the making, especially when anchored in a seaway. Transom exhaust can pick up water and pitch/roll it down the hose into the engine. No surprise really but even many factory installed exhausts are not foolproof.

I suggest you do your own research and decide what you need for your operating conditions. Read "Please Don't Drown Me" at the Northern Lights/Lugger site for the basics, the Centek site, and maybe David Gerr's book. Doing it right is expensive but the alternative is outrageous.

I agree with Brooksie. Your setup sounds like a major problem waiting to happen. I would install water lifts or whatever you need to do to get some height and slope above the waterline.

Ken

Keep in mind, you have one set of conditions when the engines are running, and you are rolling/pitching along, with the exhaust to push the water out (or up and out in the case of waterlifts) A second set of conditions in a steep following sea or backing down on a fish. And a third set of conditions when anchored in a seaway with the engines off, especially in the trades where you can be pitching for days. There are flaps and check-valves available but the each has their limitations and drawbacks. Good exhaust systems don't use jacketed risers or elbows that can fail and weep back into the engine either. A good wet system needs a water flow alarm to protect your system too; a loss of cooling water while powering and burn out your hoses and fill your bilge b/4 your coolant temp gauge tells you much of anything (if you happen to be looking at it)

I have straight pipes on my 75 MrkII as well. As far as I can tell they have been in this configuration for 30 years not counting replacement hoses. I have no issues here on the bay and it requires a whole lot less pink when I winterize.

Here you can see the port side run from the head back and I have a low spot as well. This is from when I removed the holding tank and went to a composting head.

That looks like mine. Thanks. What diameter is your exhaust hose?

3 inch I think. I can double check when I stop next time.

On The Rocks said:

That looks like mine. Thanks. What diameter is your exhaust hose?

Click to expand...

My hose is 3 inch