I have a triton tr-18 with a mercury 150 efi motor. I have just replaced the water pump impeller.the reason for this was the engine stopped after launching i trolled back to the dock and tried restart.after several unsuccessful attempts the engine started but the alarm kept sounding.I was told the impeller needed replacing because i had no water pressure and the engine wasn't discharging water.I backed the boat to motor depth today the engine fired immediatly I now have water pressure and the engine pees as my daughter says...but the alarm keeps sounding. any ideas would be greatly appreciated..thanx
<br /><br />Anyway, get a manual for your engine, Merc manuals are the best. Read it, and then read it again. It will tell you how to troubleshoot your oiling system.<br /><br />Tell then Premix your fuel at 50:1 untill you get it figured out. You might look at the oil level inside the cowling of your engine, it should be completly full, no air space at all. If its not, check that you have oil in the main oil tank and fill it. Be carefull not to over fill this tank, as it has to have about 2 inches of air space for preasure to build up. Then remove the cap on the tank under the cowling and fill with TC-W3 oil, then start the engine on muffs in the driveway and losen the cap untill oil starts seeping out then tighten it. This purges any air in the tank. If the alarm is still sounding you will have to look for other issues describbed in your manual.