Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 327Get this manual
Oil Injection Troubleshooting Chart Troubleshooting the Oil Injection System
If problem occurs with he oit injection system and the warn ing horn sounds in pulsating manner, stop engine and check if problem is caused by (1) low oil
1Open the cowling on engine and check oi level in engine reservoir tankIf oil level is not to the top of tank the problem is low oil level
There is safety reserve 01 oil left in the rese rvoir after the low oil warning is sounded that allows you enough oi for approximately hour of full throttle
operation Referto trouble shooting chart to correct the problem,