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1998 200HP EFI Merc alarm

D

drmarke

New member
"I was out today and left the

"I was out today and left the dock and got a continuous pulsing alarm. I looked in the manual and I believe this alarm represents an overheating problem. I immediately cut off the motor and waited for it to cool down to get back to the dock. After waiting 45 mins, and temp guage reading 130F and water peeing out (very hot) I went ahead and drove back to dock with the continous pulsed beeping. Even after cooling for 2 hours, I got the continous beep-beep-beep while flushing out the motor.
Q#1 - Is this the Temperature or Oil alarm?
Q#2 - If it is temperature, why didn't it just stop after I allowed it to cool?
(I plan on checking and replacing water-pump and thermastats, but wanted to use boat this weekend and it is spitting water and reading ~ 170F at its' "Hottest". I believe it may be a bad warning horn or sensor).
Anotherwards, I would rather fix the horn and save the big repair for the end of the season.
Thanks in advance Mark
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"
 
If you have an alarm it needs

If you have an alarm it needs to be checked. Sure it could be just a bad sensor in the system but why take the chance.
You have water pumping and the temp is not bad.
I would guess that you have oil as well so there is something else that has set off the alarm.

Whatever the cause is minor at this point but if you keep running it there could be more damage done.
These toys are high tech and should not be made to run after an alarm has been set off.
They didn't just put that alarm in because there were a bunch of horns around the factory that they didn't know what to do with.
I would hope you have a good enough dealer that will pull the codes for you before the weekend to see just what the problem is. This does not take long to get the codes out.
Fixing it before the weekend may be a different story but at least you can find out if it is a false alarm or not.
This is just my opinion of course and doesn't mean much.
But I am sure that doing home repair on this engine is not a very good idea no matter what anyone tells you.
That is unless you have alot of money to spend fixing it after it gets screwed up by trying to repair it yourself without the proper test equipment.
 
"Thanks guys.
I read my Clyme

"Thanks guys.
I read my Clymers' manual about 3 times since my original post.
I am going to check exactly what the alarm sounds like, and see if it alarms when I attempt to flush it this AM. (Yes full tank of oil and will check for smoke at start-up as well)
I still believe it is a temperature alarm. The normal testing cycle beeps and then turns off when the ignition is turned on. Then, when the motor is cranked, the two-tone continuous warning sounds.
The first test will be the "Engine temperature (overheat) switch test" in the Clymers' manual.
I don't plan on any boat rides until I get this problem settled, thank you, have numerous costly mistakes in the past!
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"
 
"Well, I checked the temperatu

"Well, I checked the temperature switch at the head, and it is <u>not</u> grounded. Then I disconnected the the temperature switch and the alarm turned off. I checked the tan/blue wire at the alarm and it was <u>not</u> grounded. So I don't think there is a failure in the switch or the wiring to the horn/alarm. Next I checked the voltage from the purple wire to the alarm and it read 12.23. This indicates good wires, but reads <u>higher</u> the posted 11.4 which is supposed to indicate the ignition or the horn is bad. Which one I have no idea, and could use some help here
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"
 
Before you get to carried away

Before you get to carried away check the voltage in the battery.
The 11.4 is with a battery with 12 volts.
If you have more than 12 volts in the battery this would explain the higher reading.
Newer batteries can have almost 13 volts in them after having been charged.
I have heard of bad horns but it is rare.
For the horn to work it must have a ground. The power is normal but the grounding is not.
You need to find the source of the ground to the horn.
If you unpluged the temp sender and the alarm turned off the sender is bad. How did you test the sender? If you connect one side of a test light to the wire from the sender with the sender unpluged and the other end of the test light to 12 volts at the solenoid.There should be no light. If the test light comes on the sender is bad.(grounded)
 
"Not Me,
Thank you for your r

"Not Me,
Thank you for your response. I took out the sender and checked the continuity from the bottem of the sensor to the Tan/Blue wire and it read no continuity. I didn't put it in a container and heat up the water (like I should have) as the alarm seems to come on after about 5-10 secs of running the motor. I will try your technique and the heated water test before replacing parts because I agree it is a ground problem. I've read on other posts that people have had this problem with their oil tanks/floats not funtioning properly. Do these use a seperate alarm? And, is there a way to isolate this a potencial culprit grounding out and activating the alarm?
Thanks, Mark"
 
"Update! Ronbex you were right

"Update! Ronbex you were right!
I called a Mercury repair shop today and asked about the alarm system. The manual was confusing.
The High temperature is a continuous steady beep.
The Low Oil is an intermittent pulsed beep.
The No Oil or sensor (2) malfunction is a continuous pulsed beep. (mine)

However, the oil alarm trouble shooting section of the repair manual states that a faulty temperature sensor can be the cause of the alarm.

I checked both Thermastats and they opened at the correct temperature and visual inspection was good. I put the temperature switch in water with an Ohmeter connected to the tan/blue wire and the end of the sensor. There was no continuity at the stated temperature of 185F-195F (in fact it did not show continuity at a full boil), so I will replace this and if the alarm persists I will start the more complicated oil warning troubleshooting guidelines. I'm hoping it isn't the crankshaft driven pump
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!
I did run the boat (emergently back to the dock) when the problem first occured, so I think the oil pump is still working or the engine would have seized. Of course it could be partially functioning . <font color=""ff0000"">More to follow.
Mark</font>"
 
"<font color=""0000ff"">The la

"<font color=""0000ff"">The latest!
Worked night shift at real job, and stayed up yesterday tring to get boat to run.... without an alarm.
Tested engine mounted oil cap (worked fine), then per Clymers' I tested the motion sensor on the oil pump. (Cylmers tells you to check for voltage on the white wire (fine), and then reconnect voltage unplug spark plugs and manually turn flywheel and check for a voltage through the blue/white wire (should alternate from 4-1 V), that test is B.S., as it failed and I replaced sensor and it still alarmed ($59) no return on electrical parts. Mercury guy hooked up Ohm's meter and ran a magnet back and forth over the sensor and showed change in resistance (plus he says he's never seen that sensor fail). I proceeded to the oil output test. (Hooked up an auxillary tank with 50:1 oil mix and disconnected oil line where it enters the oil-gas mixing chamber ?terminology. Ran the boat at 1500 RPM and measured output (nl 9cc) then open the oil arm to full and repeated test at 1500 RPM and got 20cc which is also normal. Back to mercury ... surprise!! $242 for warning box on backorder. I know I could probably get it on-line, but i thought the guy deserved my buisness for all his help. At least its not the oil pump and no engine damage occured when I drove it back to the dock.
Hope this helps someone in the future. I am sure it sounds confusing/difficult, but beats just repacing parts and labor costs must be high!
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</font>"
 
"Well, It wasn't the warni

"Well, It wasn't the warning module box. It turns out the oil pump is bad and the gear on the crank shaft lost teeth, and only turns the mechanical oil pump erratically which triggers the alarm. I am planning on plugging the oil pump and mixing my gas 50:1, as the replacement of the gear is ~$1,500 - $2,000.
Mark"
 
drmarke said:
"I was out today and left the

"I was out today and left the dock and got a continuous pulsing alarm. I looked in the manual and I believe this alarm represents an overheating problem. I immediately cut off the motor and waited for it to cool down to get back to the dock. After waiting 45 mins, and temp guage reading 130F and water peeing out (very hot) I went ahead and drove back to dock with the continous pulsed beeping. Even after cooling for 2 hours, I got the continous beep-beep-beep while flushing out the motor.
Q#1 - Is this the Temperature or Oil alarm?
Q#2 - If it is temperature, why didn't it just stop after I allowed it to cool?
(I plan on checking and replacing water-pump and thermastats, but wanted to use boat this weekend and it is spitting water and reading ~ 170F at its' "Hottest". I believe it may be a bad warning horn or sensor).
Anotherwards, I would rather fix the horn and save the big repair for the end of the season.
Thanks in advance Mark
happy.gif
"
Click to expand...
I just read an article where a guy had his motor running hot while it was still peeing and it was a poppet valve that he said was on all outboard engines it is on the right hand side of the motor if you’re facing from the back down at the bottom under the bottom cawling and it was bad you might want to check that or the beeping could be your oil sensor if that’s the case you better not run it or you will destroy your engine
 
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