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raa
Senior Member
Username: raa
Post Number: 60
Registered: 02-2007
| | Posted on Thursday, October 03, 2013 - 04:03 pm: | 
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Does anyone have any information on marine muffler design.Formulas or rules of thumb or??
Seems like the displacement might play a part. I have only one muffler which actually muffles the noise which is a Wilcox/Critinton on my Dippy. I have tried to make one using pipe flanges pipes with holes in it etc and nothing seems to work. I spotted the cast iron/brass muffler in a boat with a 8 hp Lockwood-Ash which made me thing about making something similar but would like to increase the odds of it actually working.
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miro
Senior Member
Username: miro
Post Number: 723
Registered: 11-2001
| | Posted on Friday, October 04, 2013 - 07:45 am: |
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The Maxim muffler on DisPros uses 3 spiral cast pieces that slow down the gases, to cool them.
Only about 1/ half of the water comes out of the exhaust port, and the other half goes out a drain at the bottom of the muffler.
And , as you probably know, the muffler is as big as the copper jacketed cylinder.
Ernie has a really good muffler at Mystic, but had no idea what was inside.
I've seen pictures of a marine muffler, with 3 cone shaped baffles inside, and another that had baffles unevenly spaced.
I'll see if I can find them.
miro |
richarddurgee
Senior Member
Username: richarddurgee
Post Number: 3097
Registered: 11-2001
| | Posted on Friday, October 04, 2013 - 10:55 am: |
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This was on file, will look for more !
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richarddurgee
Senior Member
Username: richarddurgee
Post Number: 3098
Registered: 11-2001
| | Posted on Friday, October 04, 2013 - 11:00 am: |
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Troike
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searcher
Senior Member
Username: searcher
Post Number: 581
Registered: 10-2004
| | Posted on Friday, October 04, 2013 - 01:08 pm: |
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Here is one I am going to try.
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miro
Senior Member
Username: miro
Post Number: 725
Registered: 11-2001
| | Posted on Friday, October 25, 2013 - 08:30 pm: |
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I've used this design on several engines and it does take the bark out of the exhaust note. I put a plate on the output with a large water tight fitting. I found that on one of the mufflers, the inside cap came loose and eventually fell off the pipe, plugging the muffler.
I had to cut the mufflers open, screw the cap back on - and this time, I tack welded the cap onto the pipe - and welded to body back together.
I've been using the muffler for about 15 years and it still works OK.
miro |
ivor
Member
Username: ivor
Post Number: 17
Registered: 07-2012
| | Posted on Saturday, November 30, 2013 - 05:29 pm: |
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Have just seen Raa's post and read the very helpful responses. However, I too would be most grateful for advice and help on a suitable muffler/exhaust.
Have just restored a 3hp, 2stroke Watermota engine. It runs very well but with a straight-through 11/4inch exhaust, it is very, very loud.
Am told a 2stroke needs some back pressure for maximum efficiency.
If any member could suggest a suitable design and dimensions, this would be a great help.
I had in mind a sheet metal, tubular casing, with a simple pepper pot tube down the centre. Nothing too complicated.
Best regards,
Ivor. |
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