No, coolant only keeps the motor from freezing or overheating, it otherwise has nothing to do with the performance of an engine. You might want to see if your idle is just out of adjustment, this can happen suddenly sometimes.
coolant fan
The coolant temp sensor is probably doing its job. You may have other issues such as being low on coolant or a thermostat going bad.
It should range from 195 to 230 and any thing above that is to high!
corroded/dirty connections
Yes.
No. Excessive pressure will not cause the water to boil off quickley. It will cause the radiaor hose or other components to burst causing loss of coolant. A bad radiator cap can cause high or low pressure; low pressure will cause the coolant to boil at a lower temperature.
A dirty spark plug can cause your lawn tractor engine to run at high RPM. A bad fuel filter can also cause this.
Usually in cold weather climates it means that your cars coolant is freezing up. It will cause the engine temp to get real high as the coolant does not circulate which then also causes you to not have any heat.
Try replacing radiator cap Is cooling fan working? Make sure radiator is not plugged or dirty Check coolant level water pump
Sounds like your coolant is low or your coolant level sensor could be sticking closed after the coolant was low. with the dexcool coolant it becomes thick and cause the sensor to stick closed.
A bad spark plug or spark plug wire can cause your Kawasaki engine to miss at high rpm's. A dirty fuel filter can also cause the engine to miss.
could b thermostat going, radiator cap bad or it may just be dirty/broken down coolant that needs to be changed.