Low Oil / Oil Injection Alarm at High RPM's - Need Some Advice.

[achilles555]

I have a 1988 Mercury XR4 150. I've got her running great - but there's one last problem I can't get figured out. When I get past about 1/4 throttle, my Oil Injection Alarm starts beep - beep - beep, and won't stop until I slow the boat down to about 1/4 throttle again. It's not a constant beep, so it's not overheating. It's definitely the oil. I've replaced the sending unit, made sure that my reserve tank was full to the top, and checked both oil tanks and caps for cracks or leaks. I've also pulled the oil pump off, and inspected it for problems. Everything looks good. What's got me buffaloed is that it only starts beeping at the higher RPM's. Anyone out there have any suggestions? Thanks for the help. AC.

[zooker]

hmm not a merc guy but it does sound a bit like a partly plugged oil injector..


zooker

[1FASTLASER]

Well the first and foemost thing that I would do is disconnect the oil pump and get to premixing. If ya dont you stand a big chance of blowing the powerhead. ALL the older Mercs had the plastic oil drive gear and its not a matter of if it will fail..........its a matter of when. Trust me your motor will live a helluva lot longer by going back to premixing. But if you insist on keeping the oil system it sounds like you do have a restriction and/or a sensor problem. If you have a manual on your engine go to the section on the oil sensor and get the values for checking the sensor. Get out the ohm meter and check out the system thouroughly. Also check the caps thougoughly. No cracks,good seals etc etc

[boater]

I agree with laser .I am going to diconnect mine soon but as for the beeper the first thing I would check is the oil level in the tank on the engine ,if not topped off the buzzer will go off and if it only does it at 1/4 throttle it sounds to me like the oil in the resivior might be sloshing back tripping the float sensor. Just a thought

[achilles555]

Thanks everyone for the suggestions. I cleaned the oil pick-up tube and both tanks, made sure the motor tank was full to the brim, took apart the oil pump, bearing and shaft, and everything looked good. I even replaced the sensor and plastic bearing this morning. No luck. Same beeping. I do have some good news though, I think...

I had one last thing to try that was suggested to me by a fellow Merc owner over at iBoats. He suggested switching the wire that connects to the same post on my switch box as the number 2 cylinder. He suggested removing the wire from the number 2 cylinder, and trying it on another cylinder on the OTHER switch box. That wire regulates voltage being sent to the spark plug (I think).

Anyway, I did as was suggested...and sure enough, the beeping stopped at the higher RPM's. I'm not 100% sure what that means. Maybe a new stator? I need to find out. It's great to know that I'm on the right track, though.

It does still beep a little, but only at about 1/2 throttle. It beeps a couple of times, then stops.

Thanks again for the help. If any of this sounds familiar to you guys, let me know what your next course of action would be. AC.