Temp Guage

[lakebound]

I bought a 99' Nordic Rage last summer only 90 hours on the motor.When I bought it the guy send the only thing he had wrong with it was the temp guage would jump around and not show accurate temp. I changed out the sending unit and still no fix. Then talked to people at Nordic they told that the guages were all run into a computer and that the computer went bad and that I would have to change all of the guages. Ok no big deal. Went ahead and replaced all of the guages. That was this past winter. Took boat out yesterday with new guages and the temp guage still jumps around. Sometimes it reads fine. I put a 140 thermostat in it. It wil stay there for a little while then start jumping all over the place. Last summer it as well would sound the audible alarm when it got close to overheating. Yesterday did not have that issue. But driving a boat with non accurate temp guage is a little nerve racking. Any ideas would be greatly appreciated.

Thanks,

Pablo

[BDMar]

I need some more detail about what engine package you have. Any info or pictures of the thermostat housing would help too.
Is it stock Merc with the re-circulating water pump or is it aftermarket stuff?
The only thing I can think of that controls the gauges by computer would be the SmartCraft stuff which was introduced with the 496 I believe.

[lakebound]

I will try to get some pictures. It is a standard Mercruiser 454 mag MPI motor. It does have the standard re-circulating water pump. I was told by the guys up at Nordic that the year they built my motor (1999) they were using some sort of computer bus system that they had all of the sending units wired into. That bus system would fail and the exsisting guages would not work. So I replaced all of them with new ones, and I'm still having this problem. Hope that sheds a little light for you.


Thanks,

Pablo