Guardian Alarm Troubleshooting

[Maximus82]

I have a 2004 Seadoo Utopia 205 with a Mercury 240EFI M2. I currently am getting a constant Alarm after about 5-20mins of use. The Alarm has happened a few times this season. I performed a flush of the system and it went away. The Boat ran good for another 4 trips and then the alarm came back. I pulled it out, performed another flush and took it for another trip and it alarmed pretty quickly. I pulled it out again, replaced all spark plugs (they were overdue anyway) flushed it for 20 mins and tried a back flush through the tell-tale hole (recommended on a different thread in this forum). Took it out again and the boat ran cherry until I had her going 35-40MPH for about 10 mins. The alarm was now back. Water was flowing solid out the tell-tail and the engine did not feel hot. Mechanics are sure hard to find for these boats. I talked to one recommended by a local powersports store and he said it could be the thermostats. I was just wondering if anyone on here had any insight to what it could be. Engine starts with no trouble and does not Alarm when on the hose or idle.

 

[Tim75]

Check the temp sensors in the heads. Be careful, some versions are delicate. There is procedure in the manual.

 

[Maximus82]

Thanks Tim! My apologies, which Manual? I have the operators manual for both the boat and engine but not the service manual. The next step is definitely swapping out the sensors.

 

[Tim75]

The service manual. Avail. For d/l here.

 

[Maximus82]

Ok got the service manual. Looks like three wires and one screw to replace the temp sensor. I was unable to find the part number though for the actual sensor. Anyone know what that might be?

 

[Tim75]

You need to go to online Merc parts seller and look it up.

 

[Maximus82]

I was having a hard time finding them. looks like its one of two choices based on Engine Model #. Temperature Sensor Part #889575 or Part #885342002. I believe I need the second one as it is for engines after 2002. I will double check and edit this post once confirmed. Update: I did need the second part number and have ordered 2 replacement temperature sensors. I will update this post once they arrive, are installed and I have had a chance to run her and see if the issue is fixed. Fingers Crossed!!

 

[Maximus82]

Ok so I replaced the Alternator. After reading the service manual, The theory was that the old alternator was not putting out enough Amps to keep the battery sufficiently charged forcing the system to alarm when the battery got to low to power the EFI. The boat ran good for two full days and then I started getting an intermittent alarm (manual says this could be because sensor is out of range). I went to change the temperature sensors and found that someone had puttied or glued them in place. I was able to remove one with a 14 mm wrench but was very difficult and it seemed to have been glued in. Upon removal it was totally black and the threads were crusted with some kind of putty. The brass the sensors had become very frail. Upon trying to remove the second sensor it snapped off. I’m going to try to use a bolt extractor to remove the remaining sensor.

 

[Maximus82]

I was able to get the extractor to bite but it still won’t turn and come out. I’m currently soaking it with penetrating oil, no idea what to do after this. Any thoughts are appreciated.

 

[Tim75]

I can't help you get the old sensor out, (except to remove the cyl. head). Sensor passes into cooling water, not combustion chamber.

Since the sensor is brass screwing into an aluminum cyl. head, the only thing on the threads should be Never-Seize to keep corrosion from "locking" the sensor into the head. Probably what has happened to your old sensor.

 

[Maximus82]

Thanks Tim. It’s proven to be a challenge. Still working on it. Gave up yesterday and soaked it with penetrating oil throughout the night. Going to try again this morning.

 

[Tim75]

I would think twice about welding in a boat bilge. Especially with all the electronics still in place. Not sure brass can be tig welded. Worst case- pull the head.

 

[Maximus82]

I tried just about everything to remove that damn sensor. Wound up having to drill it out. My assumptions where correct that someone had previously drilled out the Hole and puttied a sensor in place. I wound up doing the same thing with JB Weld High Heat Apoxy. I know I could of Helicoiled new threads but after spending a good six hours over a few days trying to remove the sheered sensor, I was pretty frustrated at this point. End result is that I replaced the Alternator, Battery, put in new Plugs, Gear Lubed the Impeller Shaft and replaced both Temp Sensors. Boat has ran great (the best in years) for the past three trips with no alarms. Fingers crossed it stays that way for years to come! Next project is to lube the Stator (next season). Appreciate your feedback Tim on this project!