Mercury Alarm Question

I have seen this before and can't remember the fix, I have a 50 Hp 2 stroke, when you go over 3,000 RPM's the alrm goes off, as soon as you bring the throttle back it goes away. It seemds to be cooling ok, as the stream comes out the same all the time. I give up, what is the fix or where do I need to look?<br /><br />thanks

Re: Mercury Alarm Question

I had this problem with a few 40Hp four cylinder 2-strokes. All were on pontoons and propped appropriately. Tried this, that, and the other thing, and nothing stopped the problem. Finally took the water jacket cover off (what some might confuse with a head) and descaled the cylinder domes with milkstone remover. That always fixed the problem until the next year when the scale built-up again. And it was never thickly scaled. More like a coat of primer. That was on two of them. Even the factory couldn't figure out why on the third and they ended up replacing that motor. But I'm sure that one was a fluke. I wouldn't expect them to do that with yours.<br /><br />Please give us more information on your motor. This information might not apply. Older versions of these 40s were called Classic Fiftys, but were 45Hp. Also, are you getting a steady horn, or beep beep beep. Rapid beeps (several per second) would mean a bad warning module. Beep beep beep would mean low oil in the tank which could occur as you trim the motor and change the angle of the tank in relation to the surface of the oil inside. Hopefully it's the latter and all you have to do is add some oil to the tank.

Re: Mercury Alarm Question

thanks I will try that, I have a steady beep. It is a 2004 in which we had to replace the power head because of inproper break in.The factory is givning me the same, hymmm<br /><br />JR

Re: Mercury Alarm Question

Check out your cooling system.<br />Do not run the motor if there is no tell tale.

Re: Mercury Alarm Question

My 2002 40 4stroke EFI did the same thing-the thermostat was stuck shut. Still had the stream of water, but over 2500-3000 the horn would go and power would reduce.