Thru hull exhaust, lots of opinion but...

[followme21]

I am thinkning of putting a pair on my 1984 350 Centruy/Mercruiser...(I like some noise) my question is what type of pipe should I run? I have read where people will use exhaust tube, (which I assume is rubber or something) but I want to make a set that I can control manualy to either run the thur-hull-exhaust or down to the regular exhaust..I see Corsa make electronic control but very expensive.. I would guess regular 3" exhaust designed for automotive purpose would rust rather quickly.. maybe power coat them? would help. Or can a guy get stainless or galvanized 3" pipe.

Also when I run my boat with the muff's on land only a little bit of water actually comes out the prop.. most comes out of two little holes up underneight the lower unit. Is that would I would be replacing if I actually went through with this deal...

Thanks
look forward to hearing replies..

 

[180shabah]

Re: Thru hull exhaust, lots of opinion but...

The idle relief ports will "drop" most of the water when on land, the waterjust isn't going to go past the first hole, and snake it's way down to the next one.

Noise you will get, but that is it. Unless you are making 375+hp the factory exhaust will do just fine. Vacuum behind the prop actually negates the backpressure in the system up to that point.

 

[followme21]

Re: Thru hull exhaust, lots of opinion but...

not into that kind of h-p just a little rumble...... I dont know.... havent really decided yet if I will go through with it or not.. need to do a few more measurments..

 

[SS MAYFLOAT]

Re: Thru hull exhaust, lots of opinion but...

Years ago I put a thru-hull on an old 120 hp that was bolted to a newer outdrive. There was nothing that would adapt the two without changing maniflolds. I elected to put thru-hull on it. However, I put the exhaust low enough so that at an idle or trolling the water level would cover over the exhaust. I put the rubber flapper over the end so that it would not force water into the maniflolds while in reverse.

I liked that set up since it would only roar when the boat was up on plane. I went to a custom exhaust place and had a piece bent to my specs made out of stainless. I will say that hearing the exhaust roar is cool, but can get annoying to many others if you can muffle it down while idling or trolling. Good luck on your project.