Removing Silent Choice Exhaust ???
12-14-2014 | 03:45 PM
#32
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From: Long Island, NY
Question that pops up in my head tonight...
Why would a 525 have issue with water reversion while running silent, meaning the thru hull exhaust are blocked, diverting the pressure in the y pipe, making the exhaust go out from only one hole in the transom plate, and a lets say newer MTI that comes standard from the mold, with only one big hole below the transom plate, for the exhaust to exit below water 100% of time, except on plane of course, and they run big cam engines im sure, and they dont have problem with reversion...
What is different with these animals that avoid water reversion?
Why would a 525 have issue with water reversion while running silent, meaning the thru hull exhaust are blocked, diverting the pressure in the y pipe, making the exhaust go out from only one hole in the transom plate, and a lets say newer MTI that comes standard from the mold, with only one big hole below the transom plate, for the exhaust to exit below water 100% of time, except on plane of course, and they run big cam engines im sure, and they dont have problem with reversion...
What is different with these animals that avoid water reversion?
12-15-2014 | 08:05 AM
#33
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From: Fredericksburg, Va
I have never used the silent choice, EVER... The reversion is not from using the Silent Choice, it's the actual setup that is the problem. Because there is a hole in the bottom of the tail for the water / exhaust to flow down the Z-pipe that connects to the Y-pipe, the water dump is too far forward and the water is entering the exhaust stream too close to the collector. At idle, the engines are on the verge of reverting and with the water that close it makes it a lot easier.. Again, the use of Silent Choice is NOT the problem, it's the exhaust configuration that is causing it. I am having dry tails made that eliminate the silent choice and put the water dump 2" from the tip of the exhaust. This is going to move the water dump at least 12-15" further back and far away from the collector on the header..
12-18-2014 | 06:08 AM
#34
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From: Long Island, NY
Update: I did a leakdown test on both back motors and got pretty bad results; 70-80% leak down on two cylinders on the starboard motor and 25% leakdown on the port motor, which is a new long block with 18 hours on it. Cylinders 3 & 4 on both engines are the ones affected; those are the shortest runners on the headers. So what started as a valve spring and rocker arm replacement project has turned into that plus pulling both motors, valve jobs on 4 cylinder heads and brand new exhaust.
12-18-2014 | 06:29 AM
#35
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From: St-Hyacinthe, quebec, canada
Really ? As almost bullet proof motors, it is sad to hear. Sometimes i think black motors are much more reliable with those stock manifold and risers, less powerfull package of course but they last forever..
Good luck and keep posting your progress!
Good luck and keep posting your progress!
01-27-2015 | 12:07 PM
#36
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From: NYC
Thinking about doing this too. I believe my silent choice is seized and I don't want to buy new ones plus I don't plan on ever using it.
Is this the part for that: http://www.boats.net/parts/detail/me...1776A%202.html
Is this the part for that: http://www.boats.net/parts/detail/me...1776A%202.html
01-27-2015 | 02:44 PM
#37
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From: wisconsin
I have never used the silent choice, EVER... The reversion is not from using the Silent Choice, it's the actual setup that is the problem. Because there is a hole in the bottom of the tail for the water / exhaust to flow down the Z-pipe that connects to the Y-pipe, the water dump is too far forward and the water is entering the exhaust stream too close to the collector. At idle, the engines are on the verge of reverting and with the water that close it makes it a lot easier.. Again, the use of Silent Choice is NOT the problem, it's the exhaust configuration that is causing it. I am having dry tails made that eliminate the silent choice and put the water dump 2" from the tip of the exhaust. This is going to move the water dump at least 12-15" further back and far away from the collector on the header..
01-27-2015 | 03:00 PM
#38
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From: East Texas Waterfront- running errands if anyone asks
http://www.fernco.com/plumbing/resid...bing/qwik-caps
Never mind... Sorry about the motors.
01-27-2015 | 08:15 PM
#40
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From: Long Island, NY
Thinking about doing this too. I believe my silent choice is seized and I don't want to buy new ones plus I don't plan on ever using it.
Is this the part for that: http://www.boats.net/parts/detail/me...1776A%202.html
Is this the part for that: http://www.boats.net/parts/detail/me...1776A%202.html
http://teaguecustommarine.com/em0011...off-plate.html
It's cheaper and it's a really nice thick piece of stainless steel.. You should also replace the Y-Pipe seal and coat the entire mating surface with a heavy duty silicone.
