DF50, water alarm going off

[triggerhappy]

Bought a boat with a DF50 2002 last week. Ran it for the first time today. Went for a quick ride, running 2-3000 rpm's, for 5-10 minutes, 6000 for about a minute, and 2-3000 again for 5 minutes. Ran very smoothly.

Went out about an hour later, once again it ran smooth, but when I hit 3000revs after a few minutes the water alarm went off. Both the indicator and the sound alarm. Turned of the ignition, fired up again, and ran for 30 seconds before the alarm started again. Turned it off again, and back on, the alarm went of as soon as I shifted into gear. Turned on and of while running in between a few times, same thing. Some times it was quiet for 5-10 seconds, some times it went off almost imidetly after shifting to gear. Finally got a startup with no alarm, and was able to run at 2000 revs. Gave full throttle, the alarm went off, and the engine wouldn't rev over 3000, it started to cut, and I think I saw the "limit" light. Is there a rev limit at 3000 when engine alarm is set off?

Finally got it running with no alarm at 2000 rpm's for 15 minutes before reaching shore.

The engine is running perfectly all the time. The water from the tell-tale is barely warm, 5-10 degrees celcius over sea temperature, maximum. The exhaust does not feel hot at all. The engine block and exhaust manifold is cool enough to keep my hand on whithout any pain.

Got a statement from a Suzuki dealership from the preavious owner, stating that engine alarms were going off, but no engine malfunctions were found, neither when testing on land or in water.

Can I conclude that it is a sensor/alarm-failure, not an engine overheating problem?

How to fix the problem? The dealer obviously didn't do anything to solve it.

Is there a quick fix so I can run my boat tomorrow? Disconnect a water or exhaust sensor?

What is the best permanent solution?

Do you think the problem is a malfunctioning sensor, or can it be the alarm system itself?

Regards
Thomas

 

[clanton]

Re: DF50, water alarm going off

After you check the waterpump and thermostat. Replace or clean the pressure relief valve. You will love that job.

 

[triggerhappy]

Re: DF50, water alarm going off

Update:

Talked to the mecanic who looked at the boat earlier. They hadn't actually done anything, because they didn't get the warning at all while testing.

Tried the boat/engine again today, warning came on after 2 minutes of idleing and 3 minutes driving at low rpm's. Same as last weekend. Removed the thermostat, did not help. Alarm still going of. Checked the thermostat in a pot on the stove, worked perfectly. Put it back in and fired up, the engine had cooled of for about an hour. Alarm went of after 5 seconds of idleing. Stoped it and started, same thing.

The engine is definatly not overheating! It's barely got running temperature when the alarm comes on. Sometimes not even running temperature.

The problem must be electronic.

Sensor, engine management, og instrument?

Does all three temp sensors (block, intake manifold, exhaust manifold) provide the alarm whith info, or only the engine top/block sensor?

Does the instrument interpret info from the sensors itself, and decide when to start the alarm? Or does the engine management system tell the instrument when to set of the alarm?

 

[bezerk]

Re: DF50, water alarm going off

exhaust manifold temp most likely,the intake won't cause alarm, the computer tells the gauge to light up and alarm.

 

[triggerhappy]

Re: DF50, water alarm going off

Okey.

Fired it up again today, twice. Alarm went of 5 seconds after startup. Removed thermostat, same thing. Def. an electronics malfunction.

 

[Franck]

Re: DF50, water alarm going off

Hmm strange. Maybe its a CDI/ECU problem? (computer) Did you try to fool the CDI ?

My F40 has basicly the same thing. See my post of today. The engine basicly is ok and running fine, although it still gives the temp alarm.

Only thing I could think of is fooling the CDI with the thermistor. On my Yamaha the thermistor is signalling the CDI what temp the cooling water is. I took it out and measured the resistance.

room temp : 7 k Ohm
boiling water : 1k Ohm

I fooled the CDI by replacing the thermistor with a fixed 7k resistor on the connector. As it turns out the thermistor measures 3K when the motor is at running temps (wich is good, 3k is about 85 degrees celsius, checked that in a pan of water)

Still the CDI gives temp fault, so there's only one solution left, CDI is gone bad. (if only one of you guys tells me there's another temp sensor hidden in my block ;-) )

I have the service manual for my F40 coming, maybe you should get one for the DF too.

btw if you get a alarm 5 sec after startup, it defenately sounds like a electronics thing.

Cheers,

Franck