View Full Version : 40 hp mercury 1999-2000 alarm?


yj1990
06-29-2014, 12:56 PM
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
06-29-2014, 02:06 PM
Oil alarm?

yj1990
06-29-2014, 02:26 PM
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
06-29-2014, 02:34 PM
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
06-29-2014, 03:18 PM
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
06-29-2014, 03:28 PM
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
06-29-2014, 04:58 PM
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
07-02-2014, 09:18 PM
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.
Posted from my iPhone/Mobile device

yj1990
07-03-2014, 12:24 PM
I said hell with it and dropped it of at the shop ill post what they find thanks

JFigliuolo
07-03-2014, 02:10 PM
running lean is bad ju-ju. If your not adept mechanically, the shop is the smartest option in this case.

yj1990
07-04-2014, 07:01 AM
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
07-18-2014, 01:54 PM
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