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Mercury Alarm System Problem

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Bill Lummus

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" My '96 200 HP Mercury ha

" My '96 200 HP Mercury has an alarm problem related to oiling. The alarm sounds at low rpm but not at higher rpm. I have removed the oil feed and the oil pump is pumping oil into the fuel line, even at idle speed. The amount of oil is correct as close as I can measure it. Neither the oil level sensor or the overheat sensor is causing the problem. I have replaced the oil pump rotation sensor (which caused some change in symptoms) but the problem persists.

Any ideas, anyone? All help will be appreciated! "
 
" Bill,

What kind of sound

" Bill,

What kind of sound does the alarm produce. Is it a continuous tone, or short beeps?

Tony "
 
" It beeps. According to my m

" It beeps. According to my manual, that is the sound associated with an oiling problem. As I mentioned, I have checked both the oil level and temperature sensors and neither seems to be causing the problem.

Thanks for any ideas you have! "
 
" Bill,

Until you find the

" Bill,

Until you find the problem, I would advise you to add some oil to the fuel tank (100-1). I could tell you quite a few stories that ended in disaster, and they all began with the oil alarm sounding. It doesn't make any sense to take any chances here.

The oil pump shaft is driven by a plastic gear that fits around the crankshaft. A bad tooth on this gear is not unusual. If you remove the pump you can push against the end of the shaft with your finger, and while turning the flywheel clockwise you will be able to feel if the movement of the shaft is smooth and continuous. If this shaft is turning properly, the pump has to work. There is little that can go wrong with the mechanics of the pump.

Check all of the hoses in the oil system for leaks.

You should be able to isolate the sensor that is tripping the warning module by disconnecting them one at a time. If you disconnect all of the sensors and the alarm still goes off, then the module must be faulty as James has suggested.

Tony "
 
" Thanks very much for the hel

" Thanks very much for the help. I have isolated the sensor by disconnecting the others as described in my service manual, so I think I am doing it right. Your idea of feeling the rotation to see if it is continuous sounds like a great approach. I'll do that next. I suppose a tooth or two missing might still allow the system to pump but set off the alarm if the rotation was erratic. That might very well be the problem.

There is also a voltage test described in the manual where one connects a voltmeter into the circuit and looks for voltage variations. I've tried that test but haven't been able to make it work. My voltmeter response might be too slow and no instructions are given as to how fast the engine needs to turn over to see the voltage flux. That's the main reason why I replaced the rotation sensor.

I'll be very careful about getting oil into the engine as you advise! "
 
" Bill,
I like Tony's ide

" Bill,
I like Tony's idea but I would take it a step further. Disconnet the oil injection and mix the oil in your gas tank according to your owner books ratio. High Performance engine 25;1 Stock Mercs. 50:1. If in doubt about the ratio call:
Mercury Technical Division Phone# is
1-920-929-5040
High Performance Div. 1-920-924-2088
Chuck "
 
Have you checked the warning

Have you checked the warning horn itself? I've had several horns that were beeping because of a bad ground or the horn itslf was bad.
 
I have considered just discon

I have considered just disconnecting the oil injection and mixing the oil with the gas the old fashioned way. Has anyone done that and are you happy with the result? I would pull the oil pump drive mechanism (the shaft that connects to the gear on the crankshaft) and block the oil injection tube. Is that a good approach?

I haven't checked the horn itself. How should that be done?

Thanks for all the help!
 
" Bill,

The warning horn sh

" Bill,

The warning horn should have a test circuit. On some models the horn sounds when you turn the key to the on position, then immediately turns off. On other Mercs there is a button that you can push to test the horn. I believe the test button is on the oil tank cap, but I have not checked this out, and don't remember where it should be.

If you have the first type, which sounds automatically, there will be three wires to the horn. One will be a 12 volt line from the keyswitch. One will be a ground for the test circuit. The other will ground through the sensors on the engine and oil tank. If there is a problem with the horn, it will sound even if the wire to the sensors is disconnected. I believe this is the most common type of horn. I will look for some information for testing the other type of alarm, or maybe someone else can jump in here with that info.

Tony "
 
" My horn does the "pretes

" My horn does the "pretest" properly. When I first turn on the ignition, it sounds and then stops. It's been too cold to do any more work on the engine this week!

What would you do if the oil pump drive mechanism seems to be turning smoothly when I check it? If it turns erratically, I plan to just disconnect the oiling system and go to adding oil to the fuel rather than tear the whole engine down to replace the fiberglass/plastic drive gear. Do you know of any way to tell for sure if the drive gear on the crankshaft is defective? "
 
" Bill,

If the drive gear i

" Bill,

If the drive gear is bad it will be obvious; you will feel the shaft skipping a tooth.

Tony "
 
" Thanks very much for all the

" Thanks very much for all the help and advice! I have been out of town for a week and it will be another few days before I can try any of the good suggestions you have made. If anything unexpected turns up, I'll post a new note. "
 
I have a similar problem but

I have a similar problem but with mine the alarm stays on no matter what. It is a 90hp Mercury 2002 model. The water telltale is working and it is full of oil. The starter motor will not run execpt like the battery was flat. Tried a different battery with no change. As soon as the key is turned on the alarm comes on. If I pull start the engine the telltale is showing as usual and the oil is full.

Any ideas please
 
" Bill, I just did the premix

" Bill, I just did the premix conversion on my 94 175 max. It's very straight forward and only takes an hour or so. Go to www.rickracers.com and talk with Barbara. They sell a kit with scews and the blockoff plate along with the 1/4npt plug for the block fitting to do the whole operation for under $20 plus shipping. It took me longer to remove the hoses and tank than to do the engine work. I feel safer mixing mine now after an alarm problem too. Good luck, Bill "
 
I have a couple of questions

I have a couple of questions reguarding this post...Did Bill Lummus ever find out what the problem was???/ I have the exact same prob. with xr2 150hp merc....done all the same checks......Second of all do you have to take the oil pump off the mtr in order to mix fuel manually or can you just block off oil lines and leave it on mtr?????
 
"1999 135 Mercury - my problem

"1999 135 Mercury - my problem continuous alarm is sounding, overheating but water is pumping. What could be causing this?"
 
"cat,
I posted the same probl

"cat,
I posted the same problem with a 225 opti',solid alarm over 3000???????????????????"
 
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