1994 mercury 135 V6 warning horn alert

[kramerpage]

while trolling last weekend my warning alert started an intermittent beep, beep sound at the helm.

This motor has the oil injection blocked off kit using a 50 to 1 mix in the main fuel tank. The lubalert as mercury calls it or oil alert module is still wired to green going to coil #2, tan/blue going to pin #3 on the engine harness and finally purple going to #2 pin on engine harness.

When traveling to my fishing spot the RPM on the tach was 300 higher than normal. then I shut it off and restarted and it was back to 1000 at idle instead of 1300. I trolled for 2 hours at idle around 650 to 700 RPM no issues until the beeping started. I went right to the pisser to check water flow and it was normal. I placed my hand under it and it was hot but normal to me. I went ahead and ran it back to the dock at 4500 rpm and it stopped and then started again a few times during the 5 mile run.

Could this be a Voltage regulator issue causing this? the tachometer issue is new and the horn issue is new. I had the marina place new stats and water pump this spring which They do every 3 years. Motor starts and runs great. Thanks for any insight.

Kramer

 

[Dukedog]

first thing is tha "module" and everything oiler related needs ta be gone.. any beep, beep, beep alarm is generated by tha module itself from oiler related sensors.. any over heat is gonna be a loud, continuous beeeeeeeeeeeeeeeeep.. neither has any bearing on tha other.. completely different circuits but they jus happen ta share tha same buzzer..

you should have two reg/rectifiers.. if tach acts up again change its connection (gray wire) on tha reg/rec its on now to tha gray on other reg/rec... and check tha one it was on.. if its bad ya might as well change "both reg/rectifiers............ if ya do that ya might wanna remove tha "bullet" connections and make solder/heat shrink connections... jmo.

 

[kramerpage]

OK Thanks Dukedog.
That sounds easy to do. Remove the module. I was told to leave it and unhook the three sensor leads because it was needed for the overheat circuit and the test beep beep when you first turn on key. Heck that module could be bad so removing it sounds like a win win! i will switch grey wire to the other VR. I think i soldered those connections years ago. Thanks again.

 

[Chris1956]

The overheat alarm is caused by a sensor (tan wire) on the cylinder head. This sensor grounds when it detects overheat. Grounding activates the horn.

The rest of the oil injection circuitry should be disconnected.

BTW- Merc V6 motors can have two sensors on the heads. One for overheat and one for a water temp gauge. The temp gauge sender wire can be brown.

 

[Dukedog]

OK Thanks Dukedog.
That sounds easy to do. Remove the module. I was told to leave it and unhook the three sensor leads because it was needed for the overheat circuit and the test beep beep when you first turn on key. Heck that module could be bad so removing it sounds like a win win! i will switch grey wire to the other VR. I think i soldered those connections years ago. Thanks again.

tha "test" beeps are for oiler system only and provided by tha module, have nothn' ta do with over heat.. so "no oiler" its not needed anyway... hope it all comes together for ya.

 

[kramerpage]

Chris I saw the right and left sensors in the heads. The tan for a dash temp gauge is not connected to the harness since I dont have a temp gauge. Boy it would be slick to have one for each motor. Thanks for the insight

 

[kramerpage]

Dukedog Im removing the oiler module Saturday morning when I get to the lake. If I want to test the overheat wire to see if the alarm horn works I just ground out the tan wire going to the cylinder head sensor correct? If I wanna test the sensor itself I need to heat it up in hot water over 190 degrees with thermometer and see if the switch closes to chassis ground and record temperature? Im thinking Im in there I might as well test overheat circuit.

 

[Dukedog]

yeah, your on tha right track.. over heat sensor in starboard head.. gauge wiring is in harness all tha way to control box/dash if ya wanna install a gauge.. should be a little "pig tail" on male end (boat side) of plug at motor.. temp gauges read all over tha place though.. you will need ta verify any temp gauge readings with a "temp gun"... jmo