Monday, January 18, 2010

Cleaning, Maintenance, a Few Helpful Hints

Ok, considering I am a diesel mechanic by trade, and it is what I do, I figured maybe I would take a minute to add a bit of technical knowledge and info to the blog. Maybe a few helpful hints to go along with the never ending monologue.

A post or 2 ago I commented on how Arden had a diesel leak on the injection pump. I may have even mentioned it more than once. Not only does a leak of this type waste precious fuel, it also creates a potential environmental mess. Under normal conditions, unlike gasoline, diesel fuel is not all that flammable, so there is not a huge risk of fire or explosion, that is why diesel is the fuel of choice. So how do you deal with with this problem once you find you are leaking fuel?

First and foremost, turn off your bilge pump, and if it has an automatic float switch, disconnect it. Then comes finding the leak. Sometimes they will be totally obvious, and jump right out at you, such as the one I had on Arden. Most of the time though, they are small seeps that defy discovery. A fuel leak sometimes may introduce air into the injection system, and that will cause long starts, rough running, or an engine that will not run at all. If the engine runs, here is a pretty sure fire way to find the leak.

Clean off the engine, all the fuel lines and the area under the engine. Make sure the fuel lines are clean all the way from the engine back to the tank. Next do a manual check of every fitting and hose clamp in the system. Sometimes when you put a screw driver to the clamps, or a wrench on the banjo fittings, the source of the leak will become obvious because this clamp or that fitting was obviously loose. Don't stop there though, because the vibration that caused that particular component to loosen also worked on all the others. Check them all. Once that has been done, check all the fuel hoses, the soft lines, for chaffing and wear spots. If you find a chaffed area, and it has not worn through the outer cover, isolate the hose and hold it in position with zip ties or clamps to eliminate future chaffing and rubbing. If it the chaffing has gotten too deep, replace that entire run of hose. I strongly recommend replacing the entire hose, as a union or fitting used to patch a bad spot in the hose is just one more place for a future problem to occur.

While you are checking the lines from the tank, check all fuel filter housings. Check the filter for tightness, and if the housing has a drain, check that for seeps as well. The o-rings that seal the drain cock will swell with age and leak, as will the o-ring on a filter that has been over tightened. While you are at it, go ahead and drain off any water or sediment that may have accumulated in the filter bowl, you are there, why not knock out one more maintenance issue while you are in maintenance mode.

Lastly, check all the fittings on the hard lines, the lift pump, the injection pump, and the injectors. Put a wrench on them. Try to tighten them, but don't go crazy with the torque, if they feel tight, they are, no need on stripping them or cracking a line nut by being King Kong with the wrench.

Once you are sure that all hoses, lines, fittings, and seals are good, take a clean, white, paper towel and squeeze it around every fitting and connection. Paper towels are extremely absorbent, and the fuel will stand out against the white. If you have a very slow seep, sometimes this is the only way to find it. If you can't find the leak with the engine off, start the engine and let it run, being careful to stay clear of exposed moving parts, such as water pump and alternator belts. Fuel on the engine side of the system, ie. past the lift pump, is under pressure, so not all leaks in the system will leak with the engine off. Determine what is causing the leak. Since we now know that all the fittings are tight, one of them is causing the leak, it is time to find out why. Banjo fittings have one or two sealing washers that are sometimes referred to as crush washers. If these are leaking, replace them. If no washers are available, put a piece of crocus cloth on a flat surface, and lightly run both sides of the washer across it. Sometimes this works, sometimes it doesn't, but, as always, the best fix is to replace the bad part. If it is a hose fitting that is leaking, more than likely the hose is old, and has either softened or gotten brittle with age, and will no longer seal around the fitting. Cut the hose back, or, better yet, replace it. You can't go wrong with new hose. Ever. Pipe fittings are tapered, and up to a point, the tighter they are, the better they seal. Remove a leaking fitting, put a sealing compound such as Rector Seal or pipe dope on the threads. Do not use teflon tape, as diesel fuel can break it down. When installing a pipe fitting, make it tight, a bit more than snug, but again, don't crank down on it. Usually the fitting is brass or bronze, and the fitting is softer than the hole it goes in, and you can strip the threads off the fitting. At times a stainless steel fitting is used, and that may strip out threads of the hole if over tightened. A bit of common sense will prevail here, if the fitting still leaks after installing it, tighten it a bit more. After all this is said and done, you have probably found and fixed your leak.

Now what to do with the contaminated bilge water, old fuel, and cleaning solution that is in the bilge. One sure fire method is to use a shop vac to suck it all out, provided there is not too much of it. Put it into appropriate containers, and dispose of it properly. Most marinas or boat supply houses can direct you to where or how to get rid of this bad brew. Do not ever pump it over board, you are just asking for a fine or legal troubles, and what the heck, most of us are on the water because we love the water, so why dump that stuff into it.

If there is too much to suck up with the vac, disconnect the bilge pump hose from the through hull, if it is above the waterline. It should be, but check and make sure first. Once the hose is off the fitting, get suitably sized containers, and use the bilge pump to pump the bilge water into them. Again, dispose of this stuff correctly. When you have finished cleanup, do not forget to put the bilge hose back on the through hull, and to hook the bilge pump wiring back up correctly. No sense sinking a good clean boat.

I hope that these tips may help someone that finds themselves in the situation I was in a few days ago, with a bit of common sense, the right tools and a bit of know how, a very expensive repair can be avoided, because a slow seep will take a trained mechanic just as long to find as it would take you to find, and you don't have to pay yourself $80 an hour or more.

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