Kad42 Temperature Alarm?

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Andysim

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Can anyone solve my mystery… I have a 96 Fairline Targa with KAD 42. running approx 1000hrs. They both run up to temperature around 78deg C at around 1500RPM. The Port engine stays marginally cooler as it has the water cylinder connected. I then throttle up to around 2400 RPM just past the supercharger and the turbos take over and within 2mins the overheat alarm comes on the starboard engine. They will run all day with the superchargers. I have swapped the thermostats on the engines. She has been lifted and the outdrives checked and tested. Impellers replaced on raw water pumps. I have checked the temperature of the engines while under way using an infa-red laser thermometer both engines at 2300RPM hold steady at 85Deg C on the thermostat housing. Which suggests to me that the engine is not overheating. The oil is good and the water level is good. What else can i check?
 
Andysim said:
Can anyone solve my mystery… I have a 96 Fairline Targa with KAD 42. running approx 1000hrs. They both run up to temperature around 78deg C at around 1500RPM. The Port engine stays marginally cooler as it has the water cylinder connected. I then throttle up to around 2400 RPM just past the supercharger and the turbos take over and within 2mins the overheat alarm comes on the starboard engine. They will run all day with the superchargers. I have swapped the thermostats on the engines. She has been lifted and the outdrives checked and tested. Impellers replaced on raw water pumps. I have checked the temperature of the engines while under way using an infa-red laser thermometer both engines at 2300RPM hold steady at 85Deg C on the thermostat housing. Which suggests to me that the engine is not overheating. The oil is good and the water level is good. What else can i check?
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My Sunseeker had a similar problem which turned out to be a bad earth to the temperature gauge. I replaced the earth leads to all the gauges and what a difference it made. Worth running a wire up direct from the battery to the gauge and taking her out for a test.
 
We had exactly the same problem with one of our KAMD42A. It was the thermal switch located under the supercharger that has to come out to get at it.It is about £70.
 
Ah that's def worth a look I will see if I can get at it tomorrow. I'm not sure but I think the thermostat on the thermostat housing is the primary overheat stat and just goes open or closed in alarm condition I'm guessing somewhere near 95deg c so there must be another thermostat to control the gauge. Not sure if that one would create an overheat alarm. The electronics on these of look very simple as there is no ECU as such.
 
Andysim said:
Ah that's def worth a look I will see if I can get at it tomorrow. I'm not sure but I think the thermostat on the thermostat housing is the primary overheat stat and just goes open or closed in alarm condition I'm guessing somewhere near 95deg c so there must be another thermostat to control the gauge. Not sure if that one would create an overheat alarm. The electronics on these of look very simple as there is no ECU as such.
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The thermal switch is only connected to the alarm and warning light it has nothing to do with the gauge that's why the it doesn't read over heating. The switch is located screwed in the exhaust manifold. You can swop the switch with the other engine to prove its faulty but what you said about what's happening is exactly the same as mine.I bought my parts from R.K.marine Southampton 01489583585. You will need a long reach socket 22ml thermo switch pn.833927 £62.50 and a gasket pn.957181 £.90p + vat but free postage
Ian
 
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Hi Ian

Thanks that was really helpful. I have now confirmed that the stat in the thermostat housing in not the overheat stat just the temp. I have had a good look for the stat you talk about but it's very difficult to find ? I have the supercharger at the front with the turbos at the rear and cannot see any wiring going to anything that looks like a stat. But I'm sure there is another one to find. Could you possibly try to explain where I might find it. As you are aware they don't give you much room in these engine bays !

Andy
 
Andysim said:
Hi Ian

Thanks that was really helpful. I have now confirmed that the stat in the thermostat housing in not the overheat stat just the temp. I have had a good look for the stat you talk about but it's very difficult to find ? I have the supercharger at the front with the turbos at the rear and cannot see any wiring going to anything that looks like a stat. But I'm sure there is another one to find. Could you possibly try to explain where I might find it. As you are aware they don't give you much room in these engine bays !

Andy
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Try looking at the underside of exhaust manifold almost inline with the back of supercharger, I will warn you its not easy to get at.
 
Andysim said:
Hi Ian

Thanks that was really helpful. I have now confirmed that the stat in the thermostat housing in, not the overheat stat just the temp. I have had a good look for the stat you talk about but it's very difficult to find ? I have the supercharger at the front with the turbos at the rear and cannot see any wiring going to anything that looks like a stat. But I'm sure there is another one to find. Could you possibly try to explain where I might find it. As you are aware they don't give you much room in these engine bays !

Andy
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Hi Andy
I agree it's hard to find it but unless you remove the s charger you will never find it.Its not a thermostat as you mention as such it looks more like a spark plug hence the need for the long reach socket.You will just have to bite the bullet and get the spanners out it ain't easy but it is there. Good luck.
Ian
 
All done working perfectly thanks for all of the advice ! What a place to put a sensor!!!! At least I know the engine a little better.:encouragement:
 
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