40 hp mercury 1999-2000 alarm?

[yj1990]

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

[nightfighter]

Oil alarm?

[yj1990]

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.

[piemma]

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.

[Clammer]

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 ;

[yj1990]

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.

[yj1990]

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.

[sburnsey931]

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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[yj1990]

I said hell with it and dropped it of at the shop ill post what they find thanks

[JFigliuolo]

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

[yj1990]

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.

[yj1990]

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