Soot exhaust leak

Just wanted to give everybody an update on what I discovered with the exhaust soot leak. I removed the exhaust system by removing a slice blanket to reveal a stainless bellows section with special v clamp that was removed. I then unbolted both turbo flanges and removed the 2 sections of exhaust system and put on the tailgate of the pickup and took cutoff wheel and neatly trimmed 3” off end run of Hardcoat insulation at the juncture to the mix can and discovered an unbounded weld line on the crown weld that allowed a small raw water leak to saturate the insulation end up about 2” to the weld that connects the can to dry part of exhaust and over time corroded out that weld which then allowed dry exhaust soot to pressurize the hard coat insulation assembly and exit at any tab or probe or end run of the insulation. Anyway noticed as well that design of the mixing can and it’s placement allow s total drainage of can when engine turned off Anyway I had weld shop reweld the can onto the dry exhaust pipe section and reweld the crown weld on the mix can. I then carefully reposition the insulation section and sealed the joint and with high temperature mortar caulking used by wood stove and furnace people and comes in caulk tube and dries black the same color as Hardcoat. Anyway I am going with this repair method for $150 bucks I got new gaskets and v clamp from marine exhaust systems in fla I also discovered that the engine air filters were impacted with soot so that even though the leak was minor it over time starved the engine. Not good !

Sent out oil for analysis and came back with no appreciable soot but an alarming amount of iron Aluminium and some chrome as compared to the other engine They recommend checking air clean ers and exhaust which I am doing. Had FDDA remove injectors and boroscope all 8 cylinders and discovered on this engine with 3200 hrs no indication of broken rings or cylinder parts but a lot of rust and condensation from sitting around. The crosshatching was still evident. Had injectors tested and were not popping according to spec according to nozzle master what ever that means. Anyway having new MTU injectors installed on that engine The previous owner in 2016 had replaced them with remans in south Florida about 400 hrs ago so don’t know what I’ve really got so going with new ones FDDA says do not use remans injectors in marine engines. I am wondering if I should get them for the other engine as well. The engine s do not reach full rpm especially the port engine which is why I am digging into all this and getting to the bottom of it engine wise first before I remove the props and take pitch off them. I know that this is a lot of information but while I have your attention wanted run it by you all

I think that is part of the problem they just sit up on the hard for 6 months in port Canaveral with the exhaust openings and dual air filter openings next to huge air boxes that are a conduit of humid air to the cylinders and then the rig is launched and the stern is back against a concrete seawall 8’ high and 4’ away Fromm the exhaust exits and sits some more without use. Anyway I am going to come up with an improved storage system of blocking the openings to the engine and blocking the air boxes and installing dehumidifier in engine room during storage season and then of course when launched activating engine every week. By the way what prevents me starting the engines on the hard every now and then with raw water cooling belt off?

The FDDA tech didn’t mention anything about the valves. Don’t know whether they looked at them or not They seem to be satisfied with finding so much condensate and rust stain lines at the piston circumference line that that was the culprit that was causing the wear metal in the oil when the engine is run would scrape into oil as it went up and down to clean it off. I n regard to my other question about the injectors and get new ones instead of remans don’t the new ones come set up correct with out the need to test? I n regard to starting the engine on “hard” the water pump belt would be off. It has its own belt

I m confused I was under the impression that new injectors from MTU part number whatever they say for that engine at $450 ea. Were the genuine article of choice The FDDA people say this is the way NOT. reman of any kind