Exhaust System

Project Logs

December 30, 2011

I’ll be building and installing the supports for the waterlift muffler this weekend.  I’ve had a tough time determining exactly where the muffler will go, because Beta Marine suggests/requires a 9″ drop from the outlet of the exhaust mixer elbow to the top of the water-lift muffler body (or the inlet on the muffler, depending on who you talk to).

When planning the location of my water-lift muffler, I originally had this understanding incorrect as thought the measurement was to the inlet on the water-lift muffler which is 3″ lower than the top of the body. Now, when measuring from the top of the water-lift muffler body to the top outlet of the exhaust mixer elbow, I find that I only have 6″ drop between the two. There really aren’t any other locations where I could place the muffler that would be any lower than this 6″, as I built a diesel tank in the bilge.

I plan to have a valve at the transom that I will always open when the engine needs to run, and close after the engine has stopped. My thinking is that I will make this a habit, so any water flowing back into the engine won’t really be an issue and this 12/9″ drop requirement is less important. I spoke with Beta Marine and also posted a question over at the Plastic Classic Forum and determined a fix.

The solution I’ve come to is to add a SS pipe extension to the already “high rise” exhaust mixing elbow that is installed on my Beta 14. This will raise the exhaust mixing elbow to the required 9″ above the muffler. I would have preferred to place the muffler in a lower location, but the limitations in the engine room and below cockpit area prohibited this.  For reference, here’s an image of a template of a waterlift muffler placed below the engine.  It would be too tall to be placed here, because of the sump on the engine:

An image showing a template of the footprint of a water-lift muffler placed above the bilge diesel tank, and below the engine mounts. Not enough room for the muffler here!

December 29, 2011

I’ve routed 2″ exhaust hose out below the cockpit, through the lazarette bulkhead, through a lazarette “splitter” bulkhead and through the lazarette locker sole to test to see if the 2″ hose would be able to make the required bend.  To do so, I had to use a 2 1/2″ hole drill and then slowly pulled the hose through the openings.  Happily, I found that the exhaust line ran fine and would have the required 18″ loop above the waterline where the exhaust will exit via the transom.  Here’s an image of how the loop looks in the lazarette locker:

Image showing 2″ exhaust hose looped in the lazarette locker.


 Anti Siphon Valve
Heat Exchanger
Inlet & Outlet Location
Waterlift Muffler

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