Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 372Get this manual
ProblemOil Level in Engine Oil Reservoir Tank is Low But Not Low in Remote Oil TankPossible Cause Fill cap is leaking air on the remote tankQuick disconnect on remote oil tank is not fully connected Remote oil hose (blue stripe) is blocked Remote pulse hose (second hose) is blocked or puncturedRemote pulse hose check valve is faulty (this valve is located at the engine end of the hose) restricted oil outlet filter in the remote tankCorrective Action Make sure O-rings or gaskets are in ptace and caps are tiQht Re-connect Check length of hose for kink Check length of hose for kink Replace check valveRemove filter and clean ProblemWarning Horn Does Not Sound When Ignition Key is Turned toONPositionPossible Cause Horn malfunction or open (tan) wire between horn and EngineCorrective Action Use jumper wire to ground tan lead (at engine terminal block) to engine groundWarning horn should sound If not, check tan wire between horn and engine for open circuit and check hornCheck if all ECU leads are connected to harness leadsIf so, ECU may be faultySee info on page 8-7