merc low oil alarm

[bigdognw]

I've read the past low oil alarm posts but did not find one that matched. Here it goes. I have a Merc 150Hp XR6 1996 model. The low oil light and alarm goes off intermittenly sometimes a minute or two sometimes 10 minutes. Seems to be getting more frequent. I'm getting oil, I've checked the float switch and I removed and inspected the drive shaft for the oil pump. I don't know if the pickup for the oil pump drive shaft is the problem. I did discover that the sensor located by the oil pump is only sensing if the drive shaft is turning by meanins of a magnet embedded in the drive shaft of the oil pump. My Tach is getting flaky also and I was wondering if the voltage regulator is the real problem for both problems? The tach when the motor is first started goes above 6000 sometimes 7000 but the motor does not sound that high. After the motor warms up the tach read correctly. The oil alarm seem to go with the tach misreading and can sometimes be silenced by tapping the trim button. Sorry for being so wordy. Thanks in advance.

 

[ODDD1]

Re: merc low oil alarm

Bigdog, the most frequent failure causing an alarm is low oil in the engine mounted tank....sometimes as little as a quarter inch of air space in the top of the tank will give an intermittent alarm...if you can get the cowl off next time it is alarming, try unplugging the blue wire coming from the float switch..if it shuts up, it is a bad float or a low tank...if not,maybe a skipping oil gear [doubtfull, they get worse rapidly],a bad oil control box, or you have a bad switch box on the ignition system...see, the oil control box compares pulses from the oil pump driveshaft to pulses from the ignition on one cylinder...if they dont match,the alarm fires...