I have a 2005 90 Hp. Merc. on my pontoon boat. I put the battery on it today for the first time in a few months and as soon as I turn the key on I got a loud buzzing in the console. It doesnt go off even after cranking. I have plenty of oil in the oil tank but thinking something is not working correctly inside hence the continuous loud buzzing...Im assuming this is the low oil alarm. Looking for anyones two cents worth on this one. Do I need to replace the whole oil tank if Im on the right path?
Thanks
Ken

Look for the 2 wires going to the sensor and un-plug 1 at bullet plug while key on. If horn stops you know you have to replace the tank.

On my 2003 50hp the float in the oil tank was saturated with oil so it dropped down and set off the low oil alarm. I found this out when I took it the Merc dealer. They unplugged the wire at the tank and I didn't replace anything. It had a sight window and I just kept an eye on it. Didn't use much oil so it was no big deal. If it is the float you can replace it if you feel the need.

Just rebuilt a 90hp Merc on a pontoon that someone decided to disconnect the oil alarm. Over a 75.00 dollar part: http://www.boats.net/parts/search/Merc/M...ENTS/parts.html

I'm with Gary on this one. If I'm not pre-mixing the oil and gas, I want a working alarm.