Johnson 2006 90 HP Overheats during idle only

I have a 2006 90 HP 2 stroke Johnson outboard. When idling the overheat indicator alarm and light will come on after about 3 to 5 minutes of idling. If I can take off before the alarms everything seems fine. At high speeds, above 2500 rpms, the warning alarm and light never comes on and the engine never overheats. The water stream seems very strong even at idle. I have put in a new water pump kit, new thermostats, and tried new temp sensors. Nothing has worked. Any suggestions ?

can you hold your finger on top of the motor for s count of 6 when the alarm is going off?can you hold your hand in the exhaust water?do you have enough exhaust water at idle?which side of the engine is giving the alarm?disconnect the sensors one at a time to find out...salt water boat?..check the compression...inspect or replace the water deflectors?..

I do not believe there are water deflectors in a 2006 model.-----------Possible there is too much exhaust in the water at high idle.

More Info: I ran the motor today using the water hose and muffs. This time I had a laser thermometer. As usual the warning signal and light came on after about seven minutes of running. No where on the motor, heads or thermostat housing did I find a reading above 150 degrees. Most readings were anywhere between 130 and 145 degrees. Yet the hot signal and light were on.

Yes there is a warning signal and light for the VRO. Actually the VRO was just replaced. The temp issue was happening before and after.

I should clarify that when I first switched out sensors I put in a different set, not a new set. So after thinking about it I decided to buy new ones. I installed the new sensors and then ran the motor for eighteen minutes with the muffs. No alarm, no light. I kept checking the heads and thermostat housing with a laser thermometer, nothing higher than 150 degrees just like before. So the real test in my opinion will be Saturday when I can get back to the lake and idle around for sometime but I think it is fixed and I have my fingers crossed. One thing I did notice was that one side ran warmer than the other, 20 to 25 degrees warmer. Is this normal - is this OK? Looking at the back of the motor the left side ran warmer (144-150 degrees) than the right side (122-126 degrees).

The thermostats are new. I replaced them right after I installed the new water pump. However I will check them out and see if the cool side is stuck open. Thanks for all the help.