Loud at Idle and slow cruise, Cummins 370

[forenic]

I have a 1990 32 sportfish w/ 370 Cummins. Exhaust is very loud at Idle and slow cruise (Before turbo kicks in). Once turbo kicks in it quiets out. Wondering what other people have in there boats? Looks like engine was upgraded to 370hp in 1997. Don't remember seeing muffler. Configuration 6" hose off engine and 2 90 elbows to transom. Doesn't have a lot vertical clearance to play with. I don't mind running fast, but I have some slow speed zones I go thru that the sound is overwhelming. This was my first season with boat, still catching up on fixing all the neglected things from previous owner.

[BarryG]

Well, if there is no muffler between the turbo and the transom, it seems to me that would explain the loud exhaust. I have a 2002 with 370, but it has a rather large muffler just before it exits out the transom. The loudness is subjective as well...

[leelambert]

Forenic, Tony@sbmar.com may have some insight if you were to email some pictures and description. I found that Tony has a lot of experience with Cummins marine exhaust systems.