Mercury 150 xr4 Constant Beep - beep - beep

[jhogue46140]

First off thanks to everyone for all of the great information on the forums. I have lurked here for a while and learned a lot. I have an 88 mercury 150 xr4 serial number OB289035. I have an alarm beep that has just started this week. It is a constant beep-beep-beep.......It starts after the engine has been running for 1 -3 minutes. It has happened once or twice before. It was 3 weeks ago when I was starting the engine and had to crank it a few times to get it to start. It started before the engine started. I had just gotten the boat and was just learning about how much to hold the key in to give the right amount of enrichment to start it. I shut the ignition off and turned the key back on and the engine started no alarm. I haven't had the alarm again until this week.

I have read through the forum and I have a seloc manual and followed the troubleshooting recommendations. Below are my findings. I would appreciate any input, help suggestions, or other troubleshooting.

1. Checked temperature - temperature gauge showed fine, water flow was good. I could hold my hand on valve covers and powerhead and it wasn't hot just warm.
2.Checked oil in reserve tank and remote tank (This engine is oil injected). Both were full.
3.Checked float with ohmmeter. Checked ok.
4.Checked voltage on alarm module (purple wire) It was 12.1 volts.
5.Checked flow of oil where oil line and fuel line meet. It produced about a good sized drop every second or less. It filled a teaspoon in about 1/2 to 1 minute. I can see white smoke coming out the exhaust also. I am assuming this means it is getting enough oil. I do however see that now the line on the oil output line is only half full with oil. since I have taken it off. I can see oil going down the line inside but it never fills back up. Should it?
6. Checked the temperature sensor with ohmmeter and it showed .5. I thought it should be either 0 or infinite. Does this mean I have a bad temperature sensor?
7.Checked voltage on both leads of the oil pump sensor with engine running. Only showed about .5 volts on both. I am guessing this means the sensor is bad?

Is it common to have to bad sensors? Thanks in advance for any help/input. Doug

 

[jerryjerry05]

Re: Mercury 150 xr4 Constant Beep - beep - beep

A steady BEEEEEP means your overheating. A Beep Beep Beep is the low oil warning signal.
The sensor in the oil resivoir is probably malfunctioning..Do you have a. resivoir on the motor? Or just the tank ?
Drain the system and clean it real good.Refill and see if that makes the difference.Jerry

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Thanks for the suggestion Jerry. I will try that. Yes, There is a reservoir on the top front of the engine. Doug

 

[CraigC]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Just a little info that you may or may not already have....the reservoir that's under the cowl on the front of the motor should be FULL - and when I say full I mean "up to the top, if I put any more oil in it'll overflow when I put the cap/float back on it, FULL". The oil level doesn't have to drop very much at all to set that alarm off, maybe an inch or so down from the top will do it. To test the float switch all you have to do is unplug it, if it stops beeping the float is setting it off and may be faulty, or low on oil in that tank.

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Hi Craig,
Thanks for the advice. The reservoir is full. I even cracked the cap ope and let it pump the oil out a little to ensure it was completely full. I have not tried to disconnect the float sensor while it was beeping. I will try that if it starts beeping again. I just picked up an oil pump sensor and swapped it out. The local mercury repair shop had a used one. They didn't have any new ones in stock and would have to order it. I thought I would try swapping it out. Thanks Doug

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

I have now swapped out the oil pump motion sensor. I have drained and cleaned the oil system. I have disconnected the reservoir float.I still have the beep. I am not sure where to go from here.

I was have reread the troubleshooting section of my manual and the only thing I haven't tried testing is the ignition system. The engine starts immediately as soon as it cranks so I wouldn't think it would be the problem. The manual says to check the voltage on the green wire coming from the switch box to the warning module for correct voltage. I can't find what the voltage should be in the manual. Does anyone know? Also would this be AC or DC voltage? Is there anything else I should check. I am about to give up and take it in to the service center. I just hate to loose use of the boat for a couple of weeks. Thanks Doug

 

[CharlieB]

Re: Mercury 150 xr4 Constant Beep - beep - beep

The green wire to the oil warning module is tapped into a lead from the ignition module to one of the coils. The oil module compares this reference signal to that pulse from the oil pump rotation sensor, any difference between the two and the system alarms.

Check for spark on the coil the green lead goes to, a faulty ignition module, no spark, and you get an oil alarm.

If ignition and rotation pulses are both good then you have a bad oil warning module. Of course this is also assuming that you have check and the oil level sensor is good.

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Hi Charlie,
Thanks for the info. I have checked the oil level sensor and it is good. Could you provide instructions on the correct way to check the oil pump sensor and the ignition pulse? Would I check with the volt meter set to ac or dc? Thanks again for the advice.

 

[CharlieB]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Oil pump sensor generates a small ac voltage as the magnet passes by the coil. In your very first post you stated that you had tested and it produced @ .5 V which should be within spec if I had the factory manual to look it up.

Test for spark. #3 or #4 ignition coil feed wire is the comparative pulse that the oil module uses. A failing ignition module on that cylinder, a poor connection on either end of that green wire, or an internal break in the wire, to that cylinder/coil, will cause an oil alarm.

Chances are that you have a bad oil module, but because there is NO RETURN on electrical parts you MUST test and be sure before you order any part.

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

When you say oil warning module do you mean the main warning module, the black square box? I am thinking this is the problem also. I have tried moving the green wire to different coils with the same results. I am going to check the voltage one last time and check for spark. If all checks ok I going to install a new module. Do these commonly fail?

Would there be any harm in disconnecting the green wire and the oil pump sensor from the warning module temporarily until the new warning module comes in? Would this turn the warning off? I am supposed to take my nephew and son out in the morning. The lake we are going to is idle only and we only use the motor to launch and load. The rest of the time we us the trolling motor. Thanks Doug

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Thought of one last question. Is there a way to test the alarm module or is it a process of elimination? Thanks Doug

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Well I am guessing it is the warning module. While I was checking for spark on all of the plugs I had no warning beeps. I had a good spark on all plugs. Went out started engine several times and no beep. Just went out one last time and started her and after a minute the beeping starts up again. Then while it was running it stopped and started intermittently with no pattern then back to a constant on. I guess I will order a new alarm module and pray it will solve the problem. Thanks Doug

 

[CharlieB]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Bingo! Process of elimination.

Only problem with running without a functioning alarm is that nagging thought in the back of your mind, "What if?"

Enjoy the outing and hope you get some fish.

 

[jhogue46140]

Re: Mercury 150 xr4 Constant Beep - beep - beep

Update on the beeping. the beeping quit and didnt happen again until the beginning of this year. Was just about to by a new alarm module when it quit again. Haven't had an issue all summer until a couple of weeks ago. It started beeping again. Havent been out for two weeks. I am going out tomorrow so I was out checking everything and noticed oil dripping.i start looking and notice the reservoir cap is cracked. So I go to the parts store and get a new one. Hook it up and started her up and the constant beeping is gone. It now just beeps when you turn the key on like it should. Could it have just been a faulty float and cap? I hope so this is a much cheaper fix than the alarm module. If it starts beeping again I am just going to replace the module.

The more I think of it it could have been leaking enough when trimmed all the way up that the float dropped enough to set off the alarm. I hadn't noticed oil until today. The old cap checkedok on the ohmmeter before. Hopefully that fixed it. Doug

 

[j_martin]

Re: Mercury 150 xr4 Constant Beep - beep - beep

There's lots of used modules around because some folks just get scared of em and take em off. CDI makes a replacement module also.

Anything from a carb or EFI will work fine. It fits the bolts, but the wires may need to be spliced, lengthened, shortened, or terminated differently, but the color code is the same. If it's an EFI going on a carb, there's an extra wire on the tank circuit that goes to the water seperator, you can ignore it. If it's a carb module going onto an EFI, you splice the extra wire in.

One thought before you get carried away. If the power is low or intermittent, you'll get either warning or power on test beeps. Check the purple supply wire. It may either be connected at a terminal strip, or connected with a bullet connector. tug on the connections with the switch on, motor off, and see what happens.

hope it helps
John