Exhaust options for merc 540 mag bravo 4v
 

Hey all,

I am in the middle of a repower of an old Bertram 25 hardtop. Pulled out the twin inline 6 292s Alpha drives and going with a single 540 Mag Bravo 4v listed at 440 horse at 4600 …some say there is a bit more in there. We are going with a Bravo 3 drive.

Any reason I should be worried about running thru prop exhaust? …sure I’d like to have a sort of sleeper of “cruiser” but also would like it to be on the quieter side of things.

Am I going to hurt the engine by running it thru the prop? Any other downsides?

Thanks for any advice/guidance.


some discussion on the engine I’m using here:

https://www.offshoreonly.com/forums/...bravo-4-a.html

I have a 7.4/Bravo 1, running through prop. My mechanic recommended using a tube vs the regular exhaust bellow, apparently the tube flows much better as it doesn't fully push everything out the prop and more out around the drive itself. I guess the exhaust system on the BBC/Bravo setup is a huge restriction in general, especially with the old style bellows (albeit dead silent). Its a bit louder but nothing compared to even the quietest through hull exhaust.

Thank You. I think this is what I will be doing. ...need to determine if Y-pipe for Alpha is same as Bravo, or I need to also buy a new Y-Pipe.