DIY Transom Exhaust?

[89cruisers]

Hey there everyone, During my first real launch of the season yesterday ran into a somewhat major problem. Since the drive is from a 233 (351) and the previous owner put in a 188 (302) the exhaust manifold outlet and the stern drive exhaust tube do not match up completely, about a 1" offset. What was done was instead of the factory coupler which wouldnt work, they used exhaust tubing. The problem is that wince there is an offset the tubing breaks where there is large stress from the offset. I see no real solution around this, so is there an easy, cheap, and legal way to have a transom exhaust?

 

[HT32BSX115]

Re: DIY Transom Exhaust?

I see no real solution around this, so is there an easy, cheap, and legal way to have a transom exhaust?

Can you be a tad more specific? Do you want to have Thru-hull or "Y-pipe" exhaust?

If you want thru-hull, you can easily cut/relocate the fittings to match.

If you want "Y-pipe", you'll have to get the correct y-pipe, manifolds & risers for your engine.



Regards,


Rick

 

[89cruisers]

Re: DIY Transom Exhaust?

I think a thru-hull? What is this Y-pipe? I just essentially want something to go from the manifold out the transom for each side? But for legal standards doesnt it need to be eblow the water line? I'm not sure how it works that's why I'm asking

 

[89cruisers]

Re: DIY Transom Exhaust?

Essentially all I would want is to run a pipe from each exhaust manifold elbow, and have it exit about 3" below the water line with an exhaust flapper on the end of the exit pipe to keep water from coming in when going slow or sitting. Is that legally and mechanically okay?

 

[fraannk]

Re: DIY Transom Exhaust?

Thru hull exhaust does not have to be below the waterline.

 

[89cruisers]

Re: DIY Transom Exhaust?

Well the reason for being below the waterline would be to keep it quite at the docks and while going slow

 

[Bondo]

Re: DIY Transom Exhaust?

Ayuh,... If you can rig it up,... Go for it...

The manifolds that came on those motors are in no way condusive to it though...
Most thru-hulls run off center riser manifolds, not logs...

Your risers are pointin' the wrong way...

 

[89cruisers]

Re: DIY Transom Exhaust?

Well I will try to rig it up alteast, would a standard tip with a internal shutter work since I want the tips about 3" below the waterline? or do I need a set like on jet boats that has the flapper outside

 

[HT32BSX115]

Re: DIY Transom Exhaust?

Have a look at the following link and you'll get the idea of how the measurements go.....

http://www.corsaperf.com/mhowtomea.htm

 

[89cruisers]

Re: DIY Transom Exhaust?

Alright thanks, what I am assuming I must do to have an exhaust below the waterline is use this http://www.macombmarineparts.com/pr...12684?osCsid=7851e5a962c74c15c7c64ce86efb1d92

then with this

http://www.macombmarineparts.com/product_info.php/products_id/12686

Over it?

 

[Bondo]

Re: DIY Transom Exhaust?

Popular tip for use with the 101-10 external flaps (sold separately) for meeting Mercury's "double flap" requirements. Models with flaps use the Non-Burn style.

Ayuh,... Thoses could be part of a decent system...

Extra shutters/ flappers are a good thing...

 

[89cruisers]

Re: DIY Transom Exhaust?

Okay good lol, now for a biggy, would anyone happen to know how for down they should go to still be able to get a good idle sound, but nothing extremly loud annyoing? I was thinking 3", maybe less?

 

[wire2]

Re: DIY Transom Exhaust?

Okay good lol, now for a biggy, would anyone happen to know how for down they should go to still be able to get a good idle sound, but nothing extremly loud annyoing? I was thinking 3", maybe less?

Your waterline will not be constant, depending on the number of people and gear on board, and the level of fuel in the tank.
If it's under the water line empty, you'll always be good.

Keep in mind, it will get considerably louder as soon as you get up on plane, and the tips are in open air.

 

[89cruisers]

Re: DIY Transom Exhaust?

I'm okay with hearing it when on a plane, I just want it to be a nice rumble when going slow