Heavy Carbon Sooting On Transom

Hi,

I would certainly try a set of 10's if there is nothing between there and 30, this will at least catch most of what would normally get through to your secondaries.

Are any finer ones available for the secondaries?

If you are only bunkering from a well maintained supplier and using automotive diesel you should get a long life out of the secondaries even if they are the same size as the primaries.

I would try a set of 10 micron fuel filters. What condition is your bottom in? Growth on your bottom and running gear would limit rpms and cause the smoking condition you're experiencing as well.

Soot

I purchased my 70 ft Stephens MY in Ft Lauderdale in 1991, boat had sat for 2 yrs prior to a refit one year prior to my purchase, I had the fuel polished by "experts" and since then to now, after 6000 hrs on my 12 V 71N's, I have never used anything other than 2 micron Racors, the fuel tanks seem now to be 95% clean as polishing cannot get behind all the baffles etc, I change them twice annually whether they need it or not, the only failures I had were in the Bahamas and Panama due to some water in the fuel where we were really close to full shutdown and all during high seas conditions.
My experience based on 19 years operation, ymmv

I also use 2 micron on my Hatteras in Florida and they sure clean up the fuel as the p.o. had a Captain who seemed a bit slow on fuel maintenance.

Hi,

I do not know the characters who wrote that or were mentioned in it but what is written needs to be taken with a grain or two of salt.

Using the Racor Vacuum gauges will give you an indication when the filters begin to foul long before any damage occurs to your fuel system.

If you get used to seeing the needles in a certain position at the same speed a variation in pressure (an increase in vacuum) can easily be noticed and monitored.

I have run CATERPILLAR 3516 Engines with Triple Racors - two in service and one standby for many thousands of hours and have never had to actually change a Racor underway and only done them on hours when doing the oil change at 1000 Hr intervals. I change the engine mounted ones at the same time both primary and auxiliary.

I have by the end of the 1000hrs had all three in service a couple of times as the vacuum has increased and the fuel pressure on the engine has dropped a bit.

One of these engines typically burns around 50 us gals an hour at cruise and pumps at least double that amount as it uses a lot for injector cooling and lubrication.

I use a biocide at bunkering time and run the fuel centrifuge 24/7 polishing the fuel.

It's not the fuel filters. It's too much diesel not too little. It might be the air filters. I'd definitely check them though because they will have sucked some of that soot in.

Running at that speed the engines are overloaded. Most likely they are overloading each time you climb a wave. Speed up, slow down or change the props.

I like Dennis use 2 micron elements in most of the boats I've run if I have a choice. If I was worried about not having enough surface area on the element I just go up one size on the filter or go from single to dual filters.

I also believe running a boat in rough weather does a better job of cleaning the fuel and fuel tanks than so call polishing does. Unless you can fully access the insides of the tank and it's baffles.

The information you are getting right here in this thread is all very good and from some of the best in the industry. BTW, how much soot are we talking about here? Is the transom slightly discolored or Black?

What condition is your bottom in? If you have growth on the hull and running gear (propellors/shafts/rudders etc), it will not only slow you down, but also cause the sootiness and loss of rpms. If your engines top out at 2800 rpms, you should be cruising them at 2200-2300 rpms and on plane (you may need to use the trim tabs to achieve on plane).

I have usually seen a lot more vaccuum on the racor's before seeing black soot, like in the neighborhood of 15" of vaccuum or at least 10". Engineers have told me that 30 microns don't allow the water to drop out and into the bowl in racors and it's best to run 10 microns. 2 microns may or may not be too fine, depending on your fuel quality and they could fowl very quickly.

I agree with everyone else's sentiments regarding fuel polishing and really like the Diesel Kleen "Clear Tank Diesel" additive to take care of Algae.

KIWI- Here in the US we do not get Automotive diesel fuel bunkered. Fuel that is bunkered is generally High Sulfur offroad diesel 99.5% of the time. The only way to get Automotive diesel fuel in your boat's tank would be to fill it up with fuel from an automotive gas station either by taking the boat there on a trailer, or fuel cans, and it's about 10-20% higher in price.

Wax holds soot much more than an unwaxed transom. Use a cleaner on the transom but no wax and it'll be less black. If the moderators allow it- I use the Collinite #920 to clean.

It's just a cleaner, no protectant. I prefer to wax all of a gelcoated boat, including the transom. I usually spray rolloff on the transom and brush it around lightly to spread it, let it sit a few minutes, brush and rinse off and it should take all of the soot off. With the diesels you have, you are going to get some discoloration of the transom after running for a while. What speed does the boat do at 2350? 13.5 knots is probably not a good speed to run, you're most likely better off staying at 10 knots, or closer to 20 knots and on plane.......

Try using a polymer product on you transom instead of wax. Something Zaino.

Soot will come off much easier with just boat soap and if you have use a detergent or degreaser to remove the soot you will not strip the polymer off in just one wash like you would with wax.