change thru hull exhaust to thru prop

[tfret]

I guess I'm getting old or something. I used to think the sound of my 5.7L thru hull exhaust on our I/O ski boat was cool. Now it's starting to annoy me. It's really loud if you are skiing behind the boat. I've also got young kids that ski and tube and I have concerns about hearing damage. I don't know what the decibles are, but it's loud. I was wondering if I could cap off the thru hull flanges on both sides, and install the Y pipe and exhaust bellows to the outdrive for thru prop exhaust? That way it could all be reversed later whenever I sell the boat. Anyone ever tried this?

 

[81 Checkmate]

Re: change thru hull exhaust to thru prop

Im thinking that would be posible. First would be, Has your Y pipe be removed? If so then most likley you will have to pull the motor to reinstall the Y pipe. You could also go with the more expensive route with Captians Call, With a flip of the switch sound is on or off. I did see a web site that sells a Y fitting that conects to your Y pipe and then to your Thru Hull pipe. I think it was called Triple Exhaust .com. Then the exhaust is going thru your prop and out the back the same time. Happy Boating!

 

[tfret]

Re: change thru hull exhaust to thru prop

There is no Y pipe now, just "S" shapped rubber exhaust hose from the risers to the thru hull flanges. I was thinking the Y pipe would be a similar rubber item that would connect the risers to the outdrive (alpha 1). Is that not correct?

 

[haulnazz15]

Re: change thru hull exhaust to thru prop

The y-pipe is a large metal pipe which goes from the risers down to the bottom of the transom plate where the two pipes join (the "y") and bolt onto the bell housing which is connected to the outdrive. The y-pipe cannot be installed with the engine in place.

 

[tfret]

Re: change thru hull exhaust to thru prop

Okie-Dokie. It isn't worth pulling the motor. I guess I'm looking at mufflers now.. Thanks for the knowledge.

 

[81 Checkmate]

Re: change thru hull exhaust to thru prop

It sounds like someone has already pulled the Y pipe out and caped it off. you have three choices!

1. Wear ear plugs while boating and always use a spotter
2. Go with the Captain's Choice
3. Pull Motor and install new Y pipe and the rest of the parts that would hook up your original Exhaust + you would also have to patch the holes in your transom area.

If i had my choice and the money i would go with #2

 

[Don S]

Re: change thru hull exhaust to thru prop

If you do decide to go with installing the Y pipe, below is a picture that shows the 88 to 95 version, without knowing what year you have makes it difficult to pick the right picture, but you will get the idea.
Right now you probably have the block off plate installed (item#10)
that would be removed that the rest of the "Stuff" in the picture would be needed to bolt up to the risers.

The Captains Call type exhaust still uses the Y pipe, along with a thruhull exhaust (Probably not the same holes as yours) with a switch so you can change from thru hull to thru prop anytime you want.

 

[StevNimrod]

Re: change thru hull exhaust to thru prop

There's another option...

4. Slip in silencers

The PO installed through hull exhaust on my boat when he had it. I went out and got a pair of "slip in silencers" from a marine performance place. They advertised 8-10 dB drop and I'd believe it. You can now talk at cruising speeds and hear the people around the boat. They set me back about $80. Might be just what you need if pulling the engine isn't worth it.

 

[twostroke87]

Re: change thru hull exhaust to thru prop

The best way to go if your concerned about selling it in the future would be to install captains choice exhaust. This would still require you install a Y pipe, but after you install it all you will have to do is flip a switch and it will be silent, flip that switch again and it will be loud.

Its excellent if you want to take your boat out late on night, but you don't wan to wake your neighbors.

Its pricey though eekk

 

[proaudioguy]

Re: change thru hull exhaust to thru prop

Quick question, why would anyone WANT the boat to be loud? I'm into hot rods and all, but it's a boat. I realize for a blown 2000 HP race boat, it's perhaps a performance benefit to have an open exhaust. I just don't see the reason anyone would intentionally make a family boat louder than it was when they got it. I'd love to make this little 140 at least 40dB quieter (silent would be great). It would be nice to be able to hear the dolphins, and birds and such, or to be able to actually talk to the person in the tube behind the boat.