Re: thermostat question
As Tashasdaddy said, it should **** all the time when running.
A thermostat that is stuck open or will not fully close, may prevent a powerhead from ever fully warming, this could lead to carbon fouling, stumbling, hesitation and all around poor performance. Although these symptoms could occur at any speed, they are more likely to affect most motors at idle when high water flow through the open orifice will allow for more cooling than the lower production of heat in the powerhead requires.
The Stevens Instrument company makes a product called Markal Thermomelt Stik. This is a physical marker that can be purchased to check different heat ranges. The marker is designed to leave a chalky mark behind on a part of the motor that will remain chalky until it is warmed to a specific temperature, at which point the mark will melt appearing liquid and glossy.
When using a Thermomelt Stik or equivalent indicator, markers of 2 different heat specifications are necessary for this test. For all models you will want a 163°F (73°C) or 170°F (77°C) marker to check for overheating and a 125° (52°C) or 140°F (60°C) marker to determine if the motor is failing to reach normal operating temperature.
(1) Start and run the engine at 3000 rpm for at least five minutes.
(2) Reduce engine speed to about 900 rpm as proceed as follows depending on the test equipment:
If using Thermomelt Stiks, make 2 marks on the top of each cylinder head (on most models, there should be a thermostat pocket on which you should make the marks), one with the low-range marker and one with the high-range marker. Continue to operate the motor at 900 rpm. The low-range mark must turn liquid and glossy or the engine is being overcooled (check the thermostats for a stuck open condition). The high-range mark must remain chalky, or the motor is overheating (check the thermostats for a stuck closed condition and then check the cooling system passages and the water pump impeller).
Hope that helps you.
8)----
If you look for the complex,
you will always miss the simple
Brian~
