Warning buzzer staying on

DonMacN · 15 July 2006, 13:57

Hi,
Sorry if this turns a bit lengthy, but I figure information = easier 'diagnosis'...
I recently bought a 2nd hand boat/engine - as described in the 'profile'. Used it last week for a 4 day cruise, and got back home with no problem. Later that evening I noticed the warning buzzer in the throttle housing staying on. This is despite the key being out of the ignition. If I disconnect the battery it goes off, then if I reconnect the battery straight away it starts again immediately. However, if I leave the battery off for a while, then reconnect, it seems to take some time to start sounding again. Don't know how long exactly. Trying to time it right now, and it's an hour passed with no buzzer. However last night, I did connect it, expected no problem and when I came out to the shed later in the evening it was sounding. I guess it's some sort of wiring fault - but it can't be as simple as a straightforward short circuit, or it would presumably start sounding as soon as the power was reconnected?? Maybe it's some sort of component that stores a charge -diode?? Sorry - but although I could construct a basic wiring diagram, I get lost when it gets to anything more complex than a fuse/switch/relay.

Any suggestions at all? I don't want to have to take it to the workshop at this stage in the season, and potentially pay labour charges for a lengthy diagnosis exercise.

Thanks

Donald

DM · 15 July 2006, 14:34

Quote:

Originally Posted by DonMacN

Any suggestions at all?

The warning buzzer should sound when the engine overheats or the oil level/flow is low(if it's a two stroke auto oil injection). Sometimes, the oil level sensor sticks open but as it happens without the ignition on, I'd suspect a short in the control box/loom.

Firstly disconnect the lead to the oil bottle sensor. If the buzzer still sounds, the fault is in the overheat circuit. Then vice versa with the overheat lead. This will give you an idea where to start looking.

It's a good idea to have a marine spec battery isolator in the circuit to save your battery if something does trip out. It's not unheard of to have a trim/tilt motor short out and start working on its own. It doesnt take long to overheat and burn itself out and the same would apply to your buzzer unit if left on for some time.

DM

Turbodiesel · 17 July 2006, 11:13

Sounds more like a control box problem to me, once the key is out there is no power going to the engines warning sensors. I would look at the control box.

DonMacN · 17 July 2006, 17:34

Hi folks,

Thanks for replying - sorry it's taken a while to get back. It gets curioser and curioser as the saying goes. I used the tried/tested technique of taking off the cowling and 'fiddling about with things'. At some point (though I can't be exactly sure why) the buzzer stopped. Fine I thought, I've just topped it up with oil (though the reservoir was already about 50% full) so it's the oil level sensor. Then when I trimmed the engine up/out again, the buzzer started again - which I think points further to that being the culprit.

Cheers