Overheating Issue

Follow the raw water from the pump to various components. I had one Detroit where the first stop was the fuel cooler and it was full of broken off zincs. On another Detroit, the raw water pump had a 2" spacer on the intake side and one of it's surfaces was warped and sometimes it allowed the pump to suck air and the motor to overheat and other times it was fine.

I also had another one where the raw water side was relatively clean and the coolant side of the heat exchanger was completely clogged with sediment.

Make sure the screen/strainer on the outside of the hull is clean. My diver forgot to clean mine and it caused me to overheat.

Hi, I'm new to this site. I have a 1988 48ss that I bought a couple years ago. My heat exchanger failed on my starboard engine shortly after I bought it. It all happened pretty fast, didn't realize it until engine started chugging, I looked back and tons of black smoke coming out from exhaust and engine room, I thought we were on fire. Not a good thing. I ended up repowering her with brand new Cummins QSC 8.3-600's. She's really fast now and pretty much mechanically a brand new boat, but it was a lot more expensive than one heat exchanger. Get that sucker looked at quick.

190 appears way to high at cruise, not convinced the problem has been solved. My temps at cruise are around 175 on both engines. The thing that bugs me is early on you said the turbo hose blew off. I assume that is the approx 2" in raw water hose going into the dump can. That is symptomatic of the dump can being clogged. Not familiar with your aftermarket dump can, but mine had many small diameter holes which would be easy to clog with sea water debris and zincs. Certainly proceed with caution and maybe schedule to look at the can dump over the winter months.

Yeah still a little to warm, ...did you do the heat exchanger in the tank?
Other wise you may have to do another overnight soak with barnacle buster again. You definitely got some of the junk out on the first soak but you may have to do a second one as I said.
The heat exchanger should look a worlds difference when you get it to the right person to have it cleaned out make sure you use somebody who knows what they're doing with a good reputation.