Merc 150 XR2 temp sender

[Boo]

Hello to all,<br /> I was reading some of the posts about beeps and continous alarms, I've am dealing with one now. I took loose the tan and blue stripped wire from the temp. sending unit and the alarm quit. pulled the sender to inspect and appears okay(no major corrosion on it),also inspected wire. So my question is; is it that simple just replace it? also when on the water I was'nt able to go much more than idle speed,is this a form of engine protection or am I looking at another problem?<br /> Thanks, Boo

 

[KCLOST]

Re: Merc 150 XR2 temp sender

The blue stripped wire shouldn't have anything to do with the alarm if it comes from the temp. sender... That wire should go directly to the temperature guage...<br /><br />But if it comes from an overheat switch and goes to the terminal block it will.. Normally that wire is black with a piece of clear tubing around it to prevent it from grounding to the block.<br /><br />We need the year and serial # of your engine to answer the idle speed problem...

 

[gashead1974]

Re: Merc 150 XR2 temp sender

Hi, I have a simular problem to you Boo. Im running a mid eighties 135 v6 merc. While out at the weekend I started to get a intermitent bleeping. I spoke to a couple of people who have told me that this alarm is used by both oil level and engine temp. Ive check the oil side of things by disconecting the 2 wires from the small tank and the alarm carried on. So next move was to disconect the thermal switch this stopped all bleeping. The problem I have now is does that mean I have a faulty thermo switch or is the engine running hot? Any ideas how I go about checking?

 

[KCLOST]

Re: Merc 150 XR2 temp sender

gas,<br /><br />Depending on the year of your motor, <br /><br />But normally on black max's the temp switch is set to go off at 240F. 180F temps is normal....

 

[Boo]

Re: Merc 150 XR2 temp sender

Hey Kc and Gh,<br /> On the original post I removed the wrong wire. The pulled wire went to the alarm module not the temp sender which made the alarm quit.I reattached the wire and started the engine then I disconnected the wires to the oil reserve float and also to the oil pump senser and the alarm still sounded. So now I'm not sure again. I'm going to replace the water pump soon(water flow not the greatest)but it still doesn't explain the continious beep. Bad module, bad GAS,bad something . KC sorry to waste your time on the orignal post.

 

[gashead1974]

Re: Merc 150 XR2 temp sender

KCLOST, Im going to change the snap switch over tonite and try it again. If the bleeping continues what would your next move be? Incase it helps, I get the normal 3 bleeps when I turn the ignition on, then it goes quite until I start it up. After about 5 seconds the intermient bleeping starts up and doesenmt stop. Ive tried running it with the cap slightly lose until the oil overflows then quickly doing it up but it made no difference. This leads me to think that the engine is either running hot or the snap switch is shot. Any pointers would be great.

 

[KCLOST]

Re: Merc 150 XR2 temp sender

Boo and gas,<br /><br />A continuous "beeeeeeeeeeeeeep" is an indication of an overheat condition (from the Temperature switch only). Find the overheat switch under the #1 or #2 cylinder.... It's most likely under the top sparkplug on the starboard bank... Follow that wire from the switch to where it connects to what is called the terminal block... Disconnect that lead from the terminal only....<br />If the alarm goes away when the engine is known to be cool (like just after start-up). The temp switch is most likely bad... You should also inspect the condition of that wire from the switch to the terminal block. If it has the insulation worn to the point that it can ground itself to the engine, that will also cause the alarm to sound...<br /><br />gas,<br /><br />In intermittent "beep,beep,beep" is an indication of an oil injection problem.... Is the alarm like that, or a constant "beeeeeeeeeeeeeeeeeeeep" like mentioned above? <br />What wire did you disconnect to stop the alarm and where did you disconnect it?

 

[gashead1974]

Re: Merc 150 XR2 temp sender

KCLOST, its a beep beep beep beep beep beep and so on not a beeeeeeeeeeeep. I have tried disconecting the 2 wires from the top of the oil tank which made no difference. It stops when I disconnect the tan and blue wire from the loom to the terminal to the left of the starter motor. This wire is attached to the terminal at the same point as the thermo switch and another wire of the same colour that come from the other head. I havent got a clue what that wire is, it looks the same as the thermo switch. Any ideas?

 

[KCLOST]

Re: Merc 150 XR2 temp sender

Ground the terminal to the block and see if the alarm changes to a constant "beeeeeeeeep" (with the ignition turned on only)...<br /><br />And what year is your motor?

 

[gashead1974]

Re: Merc 150 XR2 temp sender

Ive not had a chance to ground it yet, but I have a little more info. As I said, if I disconnect the tan&blue leading from the loom to this terminal I have just realised that the alarm is bound to stop as I imagine the signal gets sent from the terminal down this wire to the control box. So last night I disconected the other 2 wires that goes to this terminal, leaving the loom one connected. One of these wires comes from the thermal switch, if I disconect this it make no difference. If I disconnect the other one, which leads from a black box on the other side of the engine all alarms stop, including the 3 bleeps when I first turn the ignotion on. This black box has several wires going into it, I took it of last night and it is a sealed unit, with the blue from the oil tank going into it, along with a couple of wiring coming from it leading to what I guess is the oil pump. I think the engine is around 84. Thanks for your help.

 

[bdallam]

Re: Merc 150 XR2 temp sender

Gas, I just went through this with my '87 150 XR2. There are two sources of signal to the alarm module which will set off the intermitant "beep, beep, beep" alarm. One comes from a sender on the float in the engine mounted oil resevoir, (which supplies oil to the injection pump, and is refilled from the remote oil tank). The other comes from a sender which reads the rotor of the oil pump itself as it spins, lack of consistant oil pump rotor spinning sets the alarm. In my case it was the oil pump drive gear which was worn. This is a very shallow pitched nylon gear on the crank. If it's the sender from the oil pump setting the alarm, you've likely got problems which need to be addressed ASAP, and I wouldn't run the engine unless you're burning premix. The sender in the oil resevoir is easy to check, just open the lid and play with the float, If you pull the float down on it's stem it should set the alarm, lifting it back up should end the alarm. While your'e looking at it, make sure the resevoir is staying filled. BD

 

[Kybasscat]

Re: Merc 150 XR2 temp sender

Have you checked the gas/water separating filter on the driver's side? On some efi's they have a warning that is eaxacly like the oil warning beep. You can have enough water in it to make it sound and still run, the filter is like a small oil filter with a wire out of the bottom, disconnect the wire and see if it goes away. <br /><br />good luck<br />kybasscat

 

[Kybasscat]

Re: Merc 150 XR2 temp sender

Have you checked the gas/water separating filter on the driver's side? On some efi's they have a warning that is eaxacly like the oil warning beep. You can have enough water in it to make it sound and still run, the filter is like a small oil filter with a wire out of the bottom, disconnect the wire and see if it goes away. <br /><br />good luck<br />kybasscat

 

[KCLOST]

Re: Merc 150 XR2 temp sender

Remove the oil pump and inspect...