mercury oil alarm problems

[1pabassman]

ok guys,i am in dire need of help,i recently installed a 1999 175hp mercury outboard on my 20ft boat,i was given this motor from my buddy after he purchased a new boat,when we took it off the boat it was on the motor ran perfect new water pump, new vst tank installed compression was 120 on all 6,now it sat on a rack in my garage for 1 1/2 years out of the weather,i never used it till now because the boat i just sold had a 175 on it,so i put it on my astro boat,pulled it out of the garage,filled the oil tanks up and started the boat up after 3 cranks,perfect i thought 3 min into the run i got the alarm going off intermittently (low oil alarm) i shut it down checked to make sure i was getting oil through the injection system everything good, then i went to pull the cap on the resivior and oil came gushing out,so my question is why did the oil gush out of the resivior? and can i get some direction on what to check on for the alarm, now it is a 1999 175 hp mercury efi oil injection, serial number is OG839532 please help as i am disabled and if i can save from taking it to a shop and fix myself would be appreciated

[TrackerPro16]

I know there were some Merc's that had a problem (I had one) that the Oil Low Alarm magnet would pop off of its mount inside the tank, letting it think the oil was low. I was able to repair it myself with some closed cell two part foam and being very careful reattaching it.
As to the pressure:
If it was very full or cold when you filled, and filled it to the top I suppose it could have pressure if it was warmer when you opened it up. Otherwise I am not sure why the oil tank would have pressure as my understanding is it is not a circulating system. Maybe a bubble?

[1pabassman]

Yeah I'm puzzled on that too yes I filled both tanks before running the motor then 20 min after I shut it down I pulled the resivior cap and the oil gushed out so I let it sit another 45min and still had the same results,I dont understand it when we pulled the motor from his boat we ran it and it ran perfect and now 11/2 yr later after sitting in a heated garage I'm having this issue,and I even pulled the plugs and squirted a little oil in the cylinders so I would not dry start them pistons

[JOE54]

that system operates under pressure from crankcase , possible check valve in block not relieving pressure, I would make sure oil pump driven gear is rotating first

[Rip Bass]

Joe54, how long should the remote tank hold pressure after shut down?I understand how the oil system works but never thought about it holding pressure.

[1pabassman]

How do I check the pump?if it is rotating,I cracked the bleeder and oil was coming out?

[silvertalon]

Does the alarm sound with "key on, engine not running"? both the engine oil tank and the motion sensor for the pump have a tan or tan/blue wire running to the "Oil warning module". With the key on, disconnect the sensors (oil cap and motion sensor), one at a time and see if the beeping quits. If not, you have a faulty oil warning module or inside switch box (if it's an ADI ignition). CDM ignition won't have sidemounted switch box's. Slight pressure in the tanks is normal. You can always unscrew the cap on the remote tank in the boat before removing the engine tank cap. This will prevent overflow. Hope this helps.

[1pabassman]

So I ended up replacing theresivior cap and oil sensor and problem solved