How can I test if thermostats are opening with out removing them

My port side is running way hotter than stbd side. After a few min idling on hose. Not sure exact temp difference. But can't touch port side too hot stbd side is warm to the touch but not too hot to hold on to. Plan to check exact temp Tom with infrared temp gun

Re: How can I test if thermostats are opening with out removing them

You've got the plan already. Get one of the Infrared Laser Temp Guns from somewhere like Harbor Freight and shoot temps on the side you're concerned about. You should be able to watch the temp rise to anywhere between 150s to 180s and then decrease back down into anywhere between 120s to 160s if the T-stat is functioning. The range is because motors are a little different between makes/models. My Evinrude 140 would open at 160 and drop the demps into the 130 range. On my Force 120, they open sooner. Overheating starts in that 180 and up range on most.

Out of curiousity, though, why not just pop the cover off and "cook" them?

Re: How can I test if thermostats are opening with out removing them

emoney said:

You've got the plan already. Get one of the Infrared Laser Temp Guns from somewhere like Harbor Freight and shoot temps on the side you're concerned about. You should be able to watch the temp rise to anywhere between 150s to 180s and then decrease back down into anywhere between 120s to 160s if the T-stat is functioning. The range is because motors are a little different between makes/models. My Evinrude 140 would open at 160 and drop the demps into the 130 range. On my Force 120, they open sooner. Overheating starts in that 180 and up range on most.

Out of curiousity, though, why not just pop the cover off and "cook" them?

Click to expand...

i may do just that.. its the only way to truly know if they are opening fully or even corroded up really bad.

Re: How can I test if thermostats are opening with out removing them

ANd they do wear out. Better to spend a little extra time so you can know the full story.

Re: How can I test if thermostats are opening with out removing them

emoney said:

ANd they do wear out. Better to spend a little extra time so you can know the full story.

Click to expand...

ok this issue is solved.. and here is the end results the t-stats were functional the issue was the crud below the t-stats was restricting the water flow on the port side.. made me a hose adapter and flushed out the engine and the lower units where the water drains out thru exhaust ducts... that is where the crud was going to the exhaust ducts...thanks guys issue resolved finally.

Re: How can I test if thermostats are opening with out removing them

Good for you. Always a "win-win" when you pull the cover and visually inspect.