Marine Exhaust Systems - How They Operate
byon 07-15-2012 at 12:07 PM (460 Views)
"Exhaust gases mixed with salt water create a hugely corrosive compound. This is why exhaust systems are typically made utilizing non-co...
Marine exhausts systems are an critical and frequently overlooked component of a marine engine. Most vessels have a wet exhaust program. Salt water is injected at the riser the outlet for exhaust from the exhaust manifold. This mixture of exhaust gas and water is then passed by way of a series of bends till it exits the boat, preferably at the stern.
Exhaust gases mixed with salt water create a highly corrosive compound. This is why exhaust systems are generally produced making use of non-corrosive components such as nitrile rubber reinforced hose (brown not green stripe), galvanized steel, fiberglass or plastic. The objective of these components, which vary in size and shape depending on the engine size and layout of the engine space, is to avoid hydraulicing of the engine. This is triggered when an engine has filled with salt water which has entered via the exhaust and can result in extensive damage if left for much more than two hours. Water enters the exhaust from wave action at stern and poor exhaust style. In some ocean conditions, such as a following sea, water can be forced back up the exhaust when the engine is not operating. Poorly created exhausts allow water to flow back and fill the waterlock/muffler box then up the hose into the exhaust manifold, by means of the exhaust valves and into the combustion chamber. With the engine complete of water the engine can not crank over as it is cannot compress water.
You will know your engine is hydrauliced if it will not turn over generally soon after a long sailing period and you have removed the starter motor and ensured it works. To eliminate water from inside the combustion chambers, first eliminate all injectors, crank engine over to blow water out, refit injectors, bleed injector lines, and start. Then leave motor running until exhaust sorted out.
Check to see that the riser is not coked up or corroded a typical issue. To check the exhaust riser get rid of the exhaust hose from the riser (typically a challenging procedure) and appear up the pipe to see if it is restricted by exhaust/salt construct up. If create up is excessive the riser will have to be removed to check the engine end of the pipe. Coke can be scraped out to give a short term fix though often the riser will have to be replaced. There are aftermarket systems which vary in good quality. Make positive you fit the right style for the application.
Make certain your water-lock is low enough and big enough to hold all the water in exhaust method. Is there a gooseneck or central vertical loop in the exhaust hose at the transom exit? Is there a siphon break and is it functioning effectively no leaking valves?
Exhaust gas is poisonous and can cause sea sickness and headaches. Replace any faulty parts immediately. Use double hose clamps on every joint or, preferably, super clamps, bolt style, and exhaust cement if want be. Hot sections should be lagged with fiberglass tape to prevent burns.
Beware of asbestos lagging. Numerous older vessels and marine engine installations had exhaust systems that were lagged with asbestos tape and rope. Asbestos sound-proofing was also common in older boats. <a href=http://www.1800cheaptools.com/titan-solar-powered-auto-darkening-welding-helmet-with-american-eagle-graphics-tit41265.html>welding helmet talk[/url]"