1999 Mercury 115 offshore

[bowl-o-tuna]

I have twin 1999 Mercury 115 offshore motors and the other day one shut down and seemed to have over heated. After I let it cool it seemed fine. My question is; Is there an automatic shutdown on this motor? Also there seems to be a temp sensor and wire coming out of the head but I have no gauge or buzzer on the dash. Is this motor/wiring harness rigged for a gauge and or temp buzzer? Is it just a matter of hooking a gauge, if so does anybody have either part numbers or schematic that I can buy the necessary parts. Any information is greatly appreciated. Thanks In advance.

 

[WillyBWright]

Re: 1999 Mercury 115 offshore

Have the motor checked out. Chances of a once-siezed outboard from overheat being just fine are slim to none. The pistons got so hot that they expanded enough to take-up the clearance between the piston and cylinder til they stopped moving. Some of the piston aluminum almost certainly welded itself to the cylinder walls. Once it cooled down, the clearance was somewhat restored and the motor was able to run in a very weakened state. Expect it to need a powerhead. Sorry for the bad news on your first visit.

Merc harnesses are wired for both a gauge and a buzzer (if they used Merc harnesses). I can't imagine any respectable facility or manufacturer rigging those without at least the buzzer. That's just plain irresponsible, yet I work on boats built that way dang near every week. They saved themselves about twenty bucks and you're looking at thousands.

The tan/blue wire would go from an overheat sensor (probably already there) to a buzzer and the tan would go from a temp sender (you install) to the gauge. But I kinda doubt they're Merc harnesses. Merc's have a buzzer.

 

[bowl-o-tuna]

Re: 1999 Mercury 115 offshore

Thanks for the info, I will have it checked out.

 

[bowl-o-tuna]

Re: 1999 Mercury 115 offshore

Hello Im just getting back to my Mercury issue. Well there is a tan wire with blue stripe coming from the head. It joins with a wire that comes from the bottom of the oil tank, then they go to the wire harness. When the wire comes out of the harness under the dash the wire is just brown, no blue stipe, but it rings continuity to the brown wire with blue stirpe. As suspected there is no buzzer. So my question is will this brown wire connect to a buzzer only or is there a way to connect to a temp sensor as well. My thought was that since it is also taking a signal from the oil tank then maybe just a buzzer.
All other wires from the harness go to the switch and motor tilt except for a black a red and a grey. Is there a standard buzzer I can buy for this? Can I also connect a temp gauge based on my latest findings?

Thanks again