54' Bertram Soot on the Transom

Injector removal DD 12 71

If the injector does not come out easily you have start the tap tap tap process, this can take close to an hour if really stuck, also, check first around the top of the sleeve with a bright light to see if any carbon is present at the rim of the sleeve, will indicate a careful removal, just takes time and patience otherwise, off come the head...

I would seriously look into the air intake in the engine room before start to mess around with the injectors and timing

I noticed exhaust stains on the exhaust blanket of my 12V71TI port side engine ... also have a good amount of soot build up on the transom and cockpit after a day of running. I have a DD mechanic coming to do some owner-assist maintenance and it's on the list of items I intend to investigate with him. In the mean time, the Spray-Nine mixed with Soft Scrub does a great job of dealing with the exhaust stains on the transom and cockpit.

Mike

Soft Scrub is an abrasive. Great for stains, but it takes off your wax. I used to run a Carver that was a big league smoker. We used a product called Roll-Off (very different from On-Off and not found at WM) that worked great at cleaning soot stains. Your mechanic will address the cause of your smoking, but the stains on the blanket make me think exhaust leak. I'd take a look at the couplings.

Several years ago I boarded a 60 Sunseeker for a run down to Florida. When inspecting the engine room I noticed that the coupling behind the turbo was badly rusted and warned the owner that it needed to be changed. Long story short, coming out of Charleston our intakes clogged, we smoked (inside and out) like a 3 alarm fire and barely limped back in on one engine. Luckily the boss was one of those who took fine care of his crew & guests and we had a wonderful 5 day vacation in Charleston waiting for parts (well, 2 of those days were spent cleaning the engineroom and stern).

Why didn't you just take the air filter element off?

You would have needed a resperator to enter the engine room. Had we been further out, been in danger or lost both engines that would have been the plan.

Had a set of 12V71TI's that we tried several different injector types in. The ones we found to reduce smoke and soot the best were the 9-hole tip ones vs. the standard 7-hole. I can only assume the fuel was atomized better with the smaller, but more numerous holes.
Another way you can find out if any injectors are not doing what they should be is with an infrared heat gun. The exhaust manifolds on those engines allow you to "shoot" each exhaust port and compare them. Do this when running at cruise after at least ten minutes to allow temps to stabilize. If I remember correctly, the forward end cylinders on each bank will be slightly cooler as that is where the cooling water enters the manifold. Anything more than a 20 degree difference between cylinders indicates something is amiss. Change that injector out and see if it comes back in line.

That's just weird ... a couple of minutes with the engine shut down was less preferable than "barely limp(ing) back in on one engine"? And while barely limping, filling the engine room with soot and washing the cylinders down with unburned fuel?

That was exactly why I didn't want to pull the air cleaners off while they were still doing something (at least one). The couplings had blown (both). Running the motors was just pumping the exhaust into the engine room. Unless we were in danger, the choices I saw were to limp at idle on one engine for 20 minutes back to the dock or wait for a tow. I didn't consider running the motors with no filters in a soot filled engine room a very good option, but I'm not an engineer. We replaced (2) couplings and (2) air filters and were on our way. What do you think the result would be had we run the motors in that environment with no filters?

You would have had about 2 percent of the smoke and soot, reduced the cylinder wear by a couple of years worth, and had power available if an emergency arose.

Other than that, just a day or so worth of cleaning.

No emergency to consider as I had just passed Ft. Sumpter, and I have to doubt that 2 % since the engine room was already filled and those boats only have passive ventilation. I was of the view that all that soot would be ingested, but again, I'm not an engineer. As to the rest, I'll try to explain that to the owner next time it happens and see what he says. Somehow though I suspect he'll be inclined to go with the 20 minute idle or a tow rather than ingesting that soot.

That soot came out of the cylinders to begin with. It was created because the clogged filters prevented sufficient air from getting into the cylinders to burn the fuel you were putting into them.

And what, there is no possibility of any kind of emergency occurring past the fort?

If you had pulled the filters off the engine would breathe and not produce 98 percent of the soot that you were worried about. What was already stuck all over the engine room would have just stayed there. If you had opened one of the engine access hatches you could have ventilated the exhaust leak, removed the heat, provided clean air and been able to watch the condition of the exhaust leak(s).

But hey, you're the captain ...

If you're familiar with the Pred., the engine hatch is in an area with very little air flow. The engine room could not be entered until the exhaust settled. Shutting both motors until it settled and voluntarily going adrift between the rock breakwaters of Charleston entrance was not a good option IMHO. Bottom line is that 6 years later the excess cylinder wear doesn't seem to have had much (any) negative effect.

Is there a nominal performance curve or table someone could share? I'm particularly interested at lower, long range cruise speed

RPM HP kts gph reference
---------------------------------------------------------
2300 1700 34 95 Extrapolated
1900 1050? 20 60 Oz, describing fast cruise
1500 600? 17? 34? Me, guessing
1300 440? 15? 25? more guessing

Oz, how far off am I? I'm thinking of buying one of these, a sweetheart,but underperforming. Alleged to make only 18kt, I can't imagine how the power could be that low. Could "small injectors" result in only 300hp each? Or is my table way wrong? Or...?

There's prop slip, geartrain, but largely should come down to HP vs speed

Thank you Captain Ralph.