Overheating exhaust into Vetus mufflers

[harvey38]

Are you a member of the Aquastar owners Facebook group?

Might be worth joining

 

[Aquastar 33 Ocean Ranger]

I’m a member of the Aquastar Owners club, didn’t know there was a Facebook group, i’ll have a look,thanks.

 

[Aquastar 33 Ocean Ranger]

Well I took the other exhaust elbow off relatively easily & it is exactly the same design as the problem one. So we will have to keep thinking. We think that maybe the muffler is sloping the wrong way & is holding too much water. So the next thing is just to lift the front of the muffler with a bit of polystyrene packing so that it drains better. Won’t know if that works until we go back in the water again.

 

[harvey38]

Well I took the other exhaust elbow off relatively easily & it is exactly the same design as the problem one. So we will have to keep thinking. We think that maybe the muffler is sloping the wrong way & is holding too much water. So the next thing is just to lift the front of the muffler with a bit of polystyrene packing so that it drains better. Won’t know if that works until we go back in the water again.

Is the assumption that too much water is creating back pressure and creating heat build up in the muffler?

I think I'd be using something a bit more substantial than a 'Bit of polystyrene' as a packer, polystyrene will compress over time and you'll be back to square one.

 

[Aquastar 33 Ocean Ranger]

I agree, it was really just a way of experimenting at first & seeing if it did make any difference before I built a proper shaped cradle. The boat is set up ashore pretty much at its proper floating level so I’ll be able to check if the muffler is sloping down. What i did notice though was that the water in the pipe was much lower in the port exhaust, about at the engine bearer height. I remember when I replaced the turbo & repaired the starboard exhaust elbow, the water was much higher.

 

[Aquastar 33 Ocean Ranger]

Well I removed the port exhaust elbow & the design inside is exactly the same as the problem one, so the overheating has to be something to do with the muffler. I have also now raised the starboard muffler slightly but also have lifted the front about 25 mm higher than the rear. Have been thinking that there is too much water laying in the exhaust before the muffler, just hoping that it works but I won’t know until i relaunch.

 

[Aquastar 33 Ocean Ranger]

Well The temperatures yesterday on a one hour trip at the exhaust sensors was 30 degrees on the port muffler & 40 degrees on the starboard problem one. So still running slightly hotter but very much better. The whole time the engines were only at 1000 to 1100 revs which was when the overheating occurred. So I would call that a success as i am now able to run both engines when going up rivers or manoeuvring.