Bukh DV20 Alarm

[david1993hunter]

Hi all,

I have a friend with a bukh dv20. When servicing we found it had no oil in it, it had leaked out from around the fuel filter.

The alarm had never gone off, but it turns out the previous owner had advised him to start the engine then switch the panel off.

Today we left the panel on, and when the engine was revved up, an alarm immediately sounded. No alarm came on when starting, but when the engine is revved up then is stopped, the buzzer will stay on til the panel is turned off.

I have a few questions for those more familiar with this engine:

Is the alarm an oil pressure alarm? Does it normally come on when the panel is turned on (pre starting) as it would in a yanmar or a beta?

The panel is not a standard bukh panel (I believe) - it has 3 lights, one says start, not sure of the middle one and the left on is similar to a handbrake light in a car.

The "handbrake" light will stay on until the engine is revved up and the alarm starts, then it goes out.

Any help much appreciated!
TIA

 

[neilf39]

If the engine is not running and the panel is turned on an oil pressure alarm will sound, as will a battery charging alarm. Once the engine is running the oil pressure alarm should go off if there is sufficient oil pressure. The charging alarm should also go off but if the idle revs are such that the alarm voltage setting is close to what is achieved at idle it can stay on or beep occasionally. It may do this on startup from cold when idle speed can be a bit lower until warmed up, hence putting on a bit of throttle when first starting to warm up the engine.

 

[AuntyRinum]

I had a boat with a Bukh DV20 saildrive. There is an alarm that will trigger when water penetrates between the two rubber membranes that keep the sea out. Best check that it's not that if it's a saildrive version.

 

[LittleSister]

It is ridiculous to turn off a warning panel to stop an alarm going off. The cause of the problem needs to be investigated to establish whether it's something serious (e.g. chronic lack of oil pressure), or the alarm going off when it shouldn't.

The standard set up is that there is a small circuit board with a few diodes and resistors on it that provides for a single alarm to be set off by any one of the three warning lights (oil pressure, engine temperature, & electrical discharge) coming on. That circuit board is somewhat prone to failing, which sets off alarms incorrectly. (There is also a later version (revised values for some of the components) that addresses the tendency of the original to sound the alarm when voltages are marginal.) I would be suspicious of this item being the cause of the alarm going off when it shouldn't, or something amiss with the oil pressure sensor.

If it's the circuit board, a replacement can be obtained from the usual Bukh part suppliers, but like most Bukh bits it's not cheap. It is a very simple circuit and should be capable of being easily repaired or replicated by any competent electronics person.

 

[david1993hunter]

Thanks for your replies.

The engine is a shaft drive so that would eliminate the water membrane.

I completely agree about the panel, I wonder did the previous owner turn the panel off to ignore the alarm!?

If the panel is switched off, would that cause the charging system to fail? For example damage the regulator on the alternator?

I will check he voltage next time I am with the owner just in case.

Would an oil pressure sensor fail if the engine is run with no oil? The oil leaked out and the owner had not noticed.

Very lucky!!

Thanks again for your help.

 

[RivalRedwing]

I agree with LittleSister re sorting the electrics, I would be inclined to fit a oil pressure gauge too so as to be better informed as to what is going on.

 

[Mort]

Could also be that the alarm is the charging alarm fault, very common on DV20's, and covered on here before, which may have masked other alarms if the panel was being switched off.

I had the same fault, and sorted it by buying components and following the guide on the inadee site mention in the link



Engine Alarm

 

[Mort]

Just to say, the address in the link may have changed, so just type Inadee in your search bar and you should find it (Westerly Fulmar)

 

[david1993hunter]

Thanks everyone for your replies, all have been really helpful! Will try all your points and let you know the outcome.

Many thanks again