Oil alarm triggers at low RPM

[azhunter]

Good morning. I have a 1985 Mercury 175HP Black Max which seems to run flawlessly. The only trouble I'm having with it is that the oil alarm is on at idle. As soon as I get over 950 RPM, the alarm goes silent and all is good. I've ran through all of the checks I can find in the service manual but can't seem to figure this one out. Does anyone have any ideas?

 

[Faztbullet]

Swap the green wire from module to cylinder #5 coil output to a different cylinder....

 

[azhunter]

Swap the green wire from module to cylinder #5 coil output to a different cylinder....

Thank you for the reply. Was this a common problem on this engine? How/why does it fix the problem? I'm currently out of town but will make the swap tomorrow and post the results. Thanks again!

 

[azhunter]

Update...
I put a new battery in and the problem went away. Never swapped the green wire but will keep that in my pocket should the problem return. For what it's worth, the green wire that Faztbullet spoke of is on the #3 cylinder.

 

[azhunter]

Update...
I put a new battery in and the problem went away. Never swapped the green wire but will keep that in my pocket should the problem return. For what it's worth, the green wire that Faztbullet spoke of is on the #3 cylinder.

Final Update...
I haven't been on this forum in years but just happened to be on and open this old thread. The new battery ended up not fixing the problem. After many failed attempts, I finally found that the one of the switch plates was bad. It was hard to diagnose because it was intermittent. The problem eventually got worse to where it wouldn't start sometimes at the lake but then it would run fine at the house. Replaced both switch plates and it has been running perfect for the past 5 years or so. I just wanted to update what the end result was. Cheers!