1999 Mercury 200hp

I just bought the boat and motor ,1999 200hp . When we started it before I bought everything work correct. On the lake Saturday it fired right up and
idled for about 10 minutes. We left the dock and the boat run fine at 3500 for about 5 minutes and then the horn came on. it beeps every 2 or 3 seconds.
The guy That sold it to me told me the top lid on the oil inside the cowl cracked and he replaced it. I can see some oil on the engine. This is the first Mercury I have owned.
The motor has not been ran much in the last years. Please look at the pictures and see if I missing a hose. One back by the spark plug and one coming from the oil tank at the T.
Thanks
Mark

Not missing a hose as thats the air valve for carbs, makes em run rich till reachs temp.

Can I run 50 to 1 gas and also run the oil injector and see if it is taking oil out of the tank?

yes...mark the tank to see if the oil level drops.

There is a quick test to confirm the oiler is working.

I would suggest doing that if you itend ot keep the oiler. The alarm could be two things. 1) Oil level (meaured in the top tank on the motor) 2) the oil pump not rotating as it should. There's a pickup somwehere in the assembly.

the test will at least show you the oiler is working and narrow down if it's a faulty sensor/alarm unit or it's something with the oil pump it'self.

i had an alarm that would go off for no reason for quite a while drove me nut's in the end it was the level sensor on the oil tank at the top of the motor that was faulty.

YES!!!! run 50-1 while you figure out the problem.
that'll save your motor.
The motor has a one way valve that sends air to the tank to push oil to the motor.
Make sure the oil tank has the cap on tight.
It needs to be pressurized to send oil to the motor.
Unhook the pressure line and remove the one way valve and try to blow back through and see if it's bad.