Exhaust stains on hull

[Russell]

Does anyone else get diesel smoke stains on their hull after every run? My white hull gets an unsightly black film all around the exhaust and I have to clean it off with soap and a sponge. Is there any way to prevent this? I tried extra wax in this area and it did not help.

[Mariner]

If you're getting excessive black soot in your exhaust, your engine may not be running properly. I forget what the different colors mean, but if it's bad enough to stain your hull after every run, then I would say you've probably got a problem.

[StockHR]

There's a product sold at West Marine called "On & Off" that works well in removing exhaust and other stains on the hull.

Mike

[Elizabeth Ann]

If you're getting excessive black soot in your exhaust, your engine may not be running properly. I forget what the different colors mean, but if it's bad enough to stain your hull after every run, then I would say you've probably got a problem.

I think he only needs to be concerned about the exhaust if it is visibly dark to the eye. The colors you refer to are either Black, Blue or White and I too forget what they mean or possibly identify exactly.

I think the some questions that need to be considered are

1) Exactly how long are his trips when staining occurs? If your running the boat hard all day I would expect some exhaust marks.

2) How anal retentive are we ? Is it a thin veneered stain that is seen from a distance of 1-2 feet or is it visible from a much larger distance. What does unsightly really mean (to Russell)? I'm somewhat anal, and the slightest stain on a boat could sometimes drive me batty.

Let us not forget that every product has slight variations and one of those variation may be the smoke at the exhaust, due to natural variations in the diesel and possibly the engine itself.

I think the important thing for Russell to consider is the consistency of the engine and how it is running. Has anything changed in the past few days, weeks, months? Has the color of the exhaust changed? Have you checked the oil? Are you burning oil? If everything appears to be fine, no oil leak or burn, and the engine is constant then I think you have nothing to worry about except how to get the stain out.

I apologize for lengthy comment, I'm currently taking a break from dissertation writing and this provided a very needed escape.

[DougSea]

If you're getting excessive black soot in your exhaust, your engine may not be running properly. I forget what the different colors mean, but if it's bad enough to stain your hull after every run, then I would say you've probably got a problem.

Black smoke is a product of incomplete combustion and can point to;

1. Too much fuel - an injector or fuel system problem
2. Not enough air - a filter or turbocharger problem (this happened to me)

As EA notes in his post - just how much smoke/soot are we talking about? Some is normal and just goes with the territory. As long as a quick scrub takes care of it I'd be happy with it.

My 2 cents.

[Mariner]

Yeah, I recalled yesterday that black soot/exhaust indicates a lean condition. This can be a problem with the injectors, or just a constricted air intake. I recall one time where we noticed a lot of black smoke and a loss of power. A quick inspection of the engine revealed that a paper tag with the writing "do not remove" had flopped over the air intake (this was on a sailboat with a small engine) and was constricting the flow. It was promptly removed.

But I also agree that it really depends on just how much soot we're talking about. Diesel boats will accumulate soot around the exhaust and on the transom even if they're running perfectly. This can be particularly bothersome with a white hull. However, if it's thick, and occurs even after a relatively short run, it's an indication of something wrong.

Can you give us an idea of your running habits, and just how much soot we're talking about?

[Russell]

We usually go out for 6 hours or more so this may be normal. When I purchased the boat last fall the hull had the soot stains and they remained almost the same all winter as we used the boat and the dock water was shut off. We cleaned and waxed the hull in the spring but were surprised that after a long day the stains were almost as bad as they were before the cleaning. There is little noticeable smoke while running and I can easily clean the stains with a spray degreasing soap and sponge. I just wondered if others had to do this too.

[chiefrcd]

I do Russell, after every day out. It's much less when I use Valve Tec Fuel, but still some diesel soot is visable. I had the turbo washed and the injectors checked and all seems fine, but there is a slight diesel soot stain. Like you, a little soap and a brush and I'm good to go.

[Denis]

I find that I have very little soot on my boat but after a weekend of running, there is a tiny bit on the boot stripe. I use simple green in a bucket cut with 50% water and a brush to remove anything my boat soap will not remove.