Marinette Boat Forum

Question, all knowing shipmates. What angle is the muffler supposed to be ? Flat ,up hill to stern or down hill to stern?
Should it hold water & if it does, does it create back pressure on engine?
Thanks, Wayne

I would say either flat or slight angle down to stern. In either case the muffler is supposed to be above the waterline. The hose should definitely travel "downhill" from the starting point at the exhaust manifold down to the muffler. An inline marine muffler is meant to fill up with some water...pretty sure the back pressure is not enough to harm anything.

http://www.centekindustries.com/install_diagrams.html (the topmost picture!)

http://www.westmarine.com/WestAdvisor/E ... tem-Basics

When you start researching wet exhaust systems you will find a lot of info about "waterlift" mufflers. These are common on sailboats but most planing/semi-planing boats do not use that type of muffler.

Thanks, Good info
Wayne

When I pulled the mufflers from my '72, they ran slightly uphill towards the transom. The hangers were still connected but could have been stretched and made the front of the muffler drop. Many of the early runabouts used to run the copper exhaust pipe under the floor, then curve it up and run out the transom at the water line. Since most of these boats had no mufflers, this acted as a "water muffler". That's what gave those boats a unique sound.

I have debated this myself, I have an all original setup with hangers on each end of each muffler and one is level and the other rises maybe 1/2" up to the rear, drives me nuts but not so much that I have ever changed it, just enough to make me curious about the same question. Logic says level or down to the rear which neither of mine do.... What started me wondering is I seem to flow water from one side very consistently and at a steady rate and the up in the rear muffler is mostly the same but with a bit of fill and dump like the old chris craft style of mufflers did.

My mufflers were trashed. All the guts were gone inside so I pulled them. I love the way she sounds straight piped. I get many compliments on her "tone". Maybe when I get older I will put mufflers back in, or maybe not...