40 hp mercury 1999-2000 alarm?
 

yesterday we were out and we had a alarm go off. looks like its a overheating alarm. it would only go off when we got around half throttle. today I checked the plugs the top and bottom plugs looked good the middle looked like running real lean. what my next step to locate whats causing this problem. I just swapped plugs last week and they looked ok so this is something new. It seems to be peeing good. any help would be great thanks scott

Oil alarm?

from what I can tell the oil alarm does a beep beep beep this just is a constant beep that gets louder. mercs do have oiling issues from what ive read on line.

I did a quick search and all I could find is the merc has 2 alarms. Temp and oil. The oil alarm is know to give a false alarm as the oil float gets a leak and sinks. I'd have a marine mechanic look at it.

If your let it sit .. then run & its back up to speed , sounds like water pump .

check to see if its peeing or anything is clogging the intake ;

it is peeing but possible the maybe the thermostat not working properly. but the middle cylinder running way to lean all of a sudden makes me alittle worried.

it is peeing but possible the maybe the thermostat not working properly. but the middle cylinder running way to lean all of a sudden makes me alittle worried.

My Mercury has 2, t-stats. At high speed the second one opens....it clogged on me.....I got home on low speed...changed both out and found the salt clog.....my boat is on a mooring so I didn't rinse out the motors often. I change them every year now and keep a spare on the boat.
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I said hell with it and dropped it of at the shop ill post what they find thanks

running lean is bad ju-ju. If your not adept mechanically, the shop is the smartest option in this case.

plus and the biggest thing is its my dads boat, if it was mine I might go thru it but with limited time I have and other stuff it might need id rather have them take care of it. This way if anything goes wrong its not my fault.

well the boat yard couldn't get the alarm to sound they did the impella and t stat and I had them tune the carbs to make sure there wasn't any lean cylinders and im happy to say she runs like a champ. cant say anything good about fishing. plenty of bait and only a few wacks and swirls. the water was running between 49 to 52 deg. wtf is going on out there. thanks for all your imput scott