Hot on one side cool on other

[bluebear57]

I have been fighting a heating problem.once you throttle up (in the lake) engine heats up very quickly,changed complete impeller assembly and installed new thermostats and with the water muffs on the gauge don’t move,but starboard side head stays slightly warm ,but the port side top cylinder it’s very warm,and I have put new head gaskets flushed it out everything I can think of don’t know why that side keeps getting so hot would appreciate any ideas

 

[Chris1956]

You might tell us year and HP of motor. Sometimes compression leak causes overheat.

 

[bluebear57]

Thank you. It’s a 89 mariner 150. Compression is good in all cylinders, it starts and idles good. How would you check for compression leaks. Thank you

 

[Chris1956]

I would check torque on head bolts, to make sure they are tight, after you installed new head gaskets.