Yamaha Rhino overheating problem

[mochoa]

went out easter weekend to Ocotillo 100 degrees outside and after a 20 minute ride came back and radiator starts spilling water out the overflow. removed front skid plate and hood to get air to radiator and cam back from another 20 minute ride and exhaust silencers (white bros.) was melting.

took it to guy and he said that if the head pressure is low the engine has to work more and is the reason it might be heating up. did pressure test on head and had 90 psi, based on what I'm told norm is 150 psi. car has not had a valve adjustments since I have owned it and not sure if previous owner did it could my low compression be due to a valve not closing (seating) properly? and the over heating?

pulled the spark plug and came out black so car is running rich which should cool it even more. and I know that flushing the radiator is a great idea, plus seeing if it has a bubble is even better but want to see if the low psi is worth perusing or prob, not the reason why its overheating? when I turn the car off and the ignition back on the fan does kick on (not sure while running) I know there are allot of variables but any input is appreciated

thanks

 

[mochoa]

did the valve adjustment and now were up to 120. I know its not perfect but better than the 90 psi.

 

[prerunner rhino]

make sure your fan is running and when you do your compression check hold the throttle wide open and there is a compression release so you lose numbers thre also

 

[mochoa]

Fan does work while car is running. I know yamaha had a problem where some would only run for 30 seconds on and off but mine works fine. Any more leads would help, any idea how much psi is lost through pressure release? thanks

 

[mochoa]

my radiator on the rhino is set up for coolant and oil. I read the owner manual and said that a cause of overheating was to much oil in the engine? I checked it and it was on top of the mark drained it out a little to the middle of the dip stick mark will run tomorrow and see if it made a difference

 

[mochoa]

problem solved. car runs great I guess just needed a valve adjustment.