Johnson overheating

[amorgan3083]

2006 Johnson 150 V6 looper is overheating on one bank. New oem water pump kit. Pees like a race horse now, but still gets too hot on one bank. Can't hold finger on the cylinder heads for longer than one second. Other bankstays like warm. Verified both T stats work by previously boiling them and cleaning them as well. Water flows out of hot bank T stat housing, and that bank stays cool if ran with no T stat. Only ran like that just for a minute or so. Switched T stats and problem stays on the same side. Running on muffs with the dual chambers not the single sided ones. Do I need to clean the cylinder head water passages? These motors are simple in design so it's frustrating not resolving this.

Thanks in advance!

 

[Chris1956]

Overheat can be caused by compression leak into water jacket. A compression test could show this.

 

[Sea Rider]

That's a 14 year oldie motor, was run in salt water all these 14 years ?

Happy Boating