MD7A alarm sounds constantly

ohlson 8.8

Mar 18, 2023
Hello Everyone!

Last year i bought an Ohlson 8.8 sailing boat with a volvo penta MD7A in it. The motor runs reasonably for its age - with one problem.
The alarm sounds the moment you turn the key. It goes constantly in a spectrum between almost inaudible and ear ripping at seemingly random times. This is both annoying but also defeats the purpose of having an alarm, because i don't know if anything is wrong

I suspect that it might be the alarm separator number 17 on this list:
But that's discontinued. My question is, how do fix this? can i replace it with some other separator or is there another likely culprit? Would it be an idea to just buy a functioning instrument panel and are there any compatibility issues i should be mindful of?

Any help would be appreciated!

best regards


Mar 10, 2016
Hi. Just from experience with other VP diesels. I’d perhaps suggest that there is a very good chance that it’s the oil pressure sensor on the engine that’s causing your issue. Just what they do when they fail or occasionally get blocked with crap and cause intermittent signals.
Not to be confused with the oil pressure sender for the gauge. That’s a separate thing. If your oil pressure on the gauge is good and you’re sure it’s not a genuine alarm…then I’d be checking this.
Other than that, there are a few things that cause the alarm to sound. High temperature and likely lack of charging too. Make sure that both are not genuinely triggering the alarm. If all is healthy, check the sensor/sender units as said. Unlikely to be the actual buzzer itself usually. There should be a test button on the dash that can prove the function of the buzzer as a test. Hope that helps.