Question: Why does my generator have water in the oil?
Answer: When installing any generator it is absolutely critical for the installer to check for water intrusion while operating the vessel. Failure to do this can lead to water intrusion into the generator engine and voided warranties.
Several issues need to be addressed when installing a generator in any boat.
- In NO case should a scoop be used. A scoop is a device that forces water into the sea water circuit of the generator for cooling the closed cooling system of the generator. Generally any device that penetrates through the hull that is not flush with the hull will cause water to be forced into the system. Since most generator installations employ a water lift type exhaust system that employs a water lift muffler and a hose with an outlet loop that goes above the engine before dropping to the hull outlet, a filling effect will occur and flood the engine.
- The installation of a siphon break is recommended when the engine is at or below the vessel water line. the purpose of the siphon break is to break the water circuit on the outlet side of the raw water system thereby preventing the siphoning action of water filling the system and engine. Siphon breaks are manufactured from various companies. In all cases the manufacturer has a recommendation as to the height requirements above the water line or generator engine. If not properly installed the water will siphon back into the system and fill the engine. This is especially true of systems that use below water exhaust outlets.
- Water lift mufflers also require attention. It is possible for water to “splash” back into the engine while running or when the engine is shut down. The installation of a water lift muffler requires a couple of points. First make certain that the drop from the exhaust outlet to the muffler meets the generator manufacturer’s recommendation. This will allow water to travel a safe distance from the engine before entering the muffler. Second make sure the muffler is large enough by volume to hold all of the water from the engine and exhaust hose after the generator has been shut down.
After you have installed your generator a few simple tests should be performed to prevent engine failure due to water intrusion.
- Start, allow to run for a couple of minutes, and stop the generator. Repeat this process several times. After a few times remove the hose that connects to the inlet side of your muffler from the exhaust elbow. When the hose is removed there should be no water spilling out of the muffler. Look into the muffler for the water level. The water level should be low enough to prevent water from rolling back into the hose during operation of the vessel.
- Remove the hose from the suction side of the sea water (raw water) pump. While underway in the vessel hold the hose at or above water line and open the sea valve. Observe whether or not any water is coming through the hose-there should be none. Reinstall the hose.
- Again start the generator and allow to come up to operating temperature. Once it has reached operating temperature shut it down. Remove the hose that attaches to the exhaust elbow from the siphon break. There should be no water dripping out of this hose for an extended period of time. If there is then the siphon break is not installed properly.
With these simple guidelines and checks you should have the reassurance that the generator will not sustain damage from water intrusion. We also realize that strange things occur beyond our control and we cannot prepare for everything. But if we cover the basics we have done our best.
ALWAYS CHECK THE INSTALLATION MANUALS FOR SPECIFIC GUIDELINES AND RECOMMENDATIONS PRIOR TO FINAL COMMISSIONING OF ANY ENGINE PRODUCT.