Mercury 200 alarm

[mad8713]

This is my first post, but i have to say the site helped me out alot already. Here we go!!!<br /><br />I recently bought a 1989 200hp mercury. On my first run with the boat the alarm started sounding when I reached 2000rpms. I checked around and bought the boat back to the rebuilder. He said the oil resevoiur was not filled up. (Did not seem right to me) Next trip out the boat ran ok but only reached 5000rpm. Then on the way in the motor stated runing great for about 30 seceends and then stated to throw up. Wouldn't reach 3000rpm. Next I replaced the stator, thanks to some research on the site. THe motor ran great. Two long days on the water motor 5800 and no alarms. On the way in the alarm starts to blow. I check everything.<br /> Ok, Just got back from a boat ride with the rebuilder. He test all the sensors. Seems ok.. Then he moved a wire on the switch box. and the alarm stoped. It seemed that the post where the wire belongs was causing the alarm to malfuntion. The alarm system works properly with the power from the post below it. <br /> Ok to the point. Why is this happening. Is the switch box bad? What will happen if i run the boat this way? Should I request him to replace any other parts

 

[KCLOST]

Re: Mercury 200 alarm

Yes?

 

[mad8713]

Re: Mercury 200 alarm

bump

 

[mad8713]

Re: Mercury 200 alarm

help

 

[KCLOST]

Re: Mercury 200 alarm

There is a wire that goes from the alarm module to one of the switchboxes... That wire is connected there to determine if the oil pump is working properly in conjuction with the amount of rpms the engine is turning (via electrical pulses going to the module).<br /><br />It's probably a green wire correct? This can be an indication of a switchbox problem, or a oil pump problem...<br /><br />You can move that wire from the post on one switchbox onto the same post on the other switchbox.. See if the alarm stays or goes away. If it goes away, you need a new switchbox...(probably two if they are the originals)<br />You can also check the spark on all the cylinders. Make sure each is equal and strong...<br />If you have a no spark condition, that can also cause the alarm as the switchbox is bad (assuming the coil is fine). A weak spark on one bank or the other, usually means a stator problem...<br /><br />Let us know...

 

[mad8713]

Re: Mercury 200 alarm

The green wire is correct. The rebuilder moved the wire to a different post in the some switchbox.(Outerswitch box). When he did this the alarm stopped. When we moved it back the alarm started. Sounds like the switchbox right?<br /><br /><br />Do the other green wires on the switchbox not have something to measure the spark for the oil pump sensor? Is that why it stopped

 

[KCLOST]

Re: Mercury 200 alarm

Yes it does....<br /><br />But I would confirm first...(but make sure the oil pump is working properly) <br /><br />However a bad switchbox, probably explains the alarm and the low rpm problem both....<br /><br />The only way I know to test a switchbox (without high tech. equipment) is by checking the spark on each cylinder.... You check it while cranking... Look for missing or weak spark on all cylinders. Then switch the stator leads from one box to another... Switch the blue and red wire from one swithcbox (at the top) with the blue/white and red/white wire from the other. If any no spark or weak spark conditions remains on the same cylinders, it's the switchbox that feeds those cylinders that is the problem.. If they move from one bank to another it's a bad stator...<br /><br />I hate for you to purchase two new switchboxes without knowing for sure.. They are not cheap, and if you don't have CDI boxes on there it's recommended to replace both of them even if only one is bad..<br /><br /><br />By the way, the other green wires (with stripes) go to the coils which sends the spark. The solid green wire we are talking about is only for the alarm module....<br /><br />Let us know...

 

[mad8713]

Re: Mercury 200 alarm

Ok Let me try to explain this the best I can<br /><br />The alarm problem stopped when I moved the the solid green wire from the alarm module to the next post on the switch box. When I moved back the alarm started again. I left the green wire on the post that did not sound the alarm. Now the boat is running good and has no alarm sounding. The warning system seems to be working properly. I was told that everything is fine and run the boat and the switch box post is not a problem because it take such a some voltage change to trip the sensor. That it won't effect the motor. Is this true??

 

[KCLOST]

Re: Mercury 200 alarm

That is true.... In regards to the switch box post voltage issue...<br /><br />But I'm worried about your rpm issue you mentioned earlier....<br /><br />If everything is working properly with the connections you have now, I wouldn't sweat over it.. But check the rpm problem... If it remains you probably have a SB problem.... If that previous post had poor voltage out of it, it will affect the engine performance.<br /><br />There has to be a reason why the alarm only goes off on one of the box terminals.........<br /><br />I have heard of conditions where the switchbox can start to fail when heated up. So try it out and let us know...

 

[ronmold]

Re: Mercury 200 alarm

You mentioned it works ok on "the post below". My wiring diagram shows that the factory location IS the bottom post on the outer box which should have the solid (no stripe) ign. coil wire on it ( cyl 2). Strange that it would matter which post it gets it's "i'm running now" tach signal from! One thought would be that the post it seems to work on is NOT giving a good pulse or spark therefore the warning module believes the engine is not running and gives no alarm. Test the oil warning system by pulling the rotational sensor wire (Lt. blu/wht) plug and then later the oil tank sensor plug (Lt. blu) while the motor is running to make sure the alarm starts beeping. It may be you have a oil inj. problem. Good Luck!!!

 

[VT911]

Re: Mercury 200 alarm

My 2001 200HP Merc is apart on my work bench right now because the oil alarm didn't sound and I fried a piston (after the main oil line got disconnected, and the reserve tank sucked dry)<br /><br />So...make sure you get it working right!<br /><br />greg

 

[restretch1]

Re: Mercury 200 alarm

Hey Mad,<br /><br />A little advice. I just had a 1988 200hp Mercury with pretty much the same problem as yours. The first time the alarm went off I didn't have the oil cap tight on the external resevoir (get it tight because if you don't it won't pump oil to the main resevoir). The second time I had a oil problem I blew a rod. The mechanic who rebuilt my carbs didn't replace the needle valves on the floats. One of the pistons wasn't getting gas or oil and the other five carried it along until poof. So heres my advice. After 4000.00 dollars in various mechanics. Find the one with the most training and no matter the cost have that guy do the work. Alot of these guys tell you the know what there doing but don't.<br /><br />Not trying to put good mechanics down just trying to help. Good luck.

 

[mad8713]

Re: Mercury 200 alarm

Kclost<br /><br />The earlier RPM problem was solved when I replaced the stator. The motor runs around 5800 at wot open throttle. That what makes me think every is running properly. Checked the oil pump and spine there was no plastic. Yesterday I ran the boat pretty hard with no problems. I think that post that the oil sender was on is on it way out. I will need a switch box soon. I will let you know.