Hello everybody!
I have a Merc 502 on my 26 and I realised that the two risers have different temperature.
The part circuit are new but the right one is quite hot (I cant't leave the hand more than 5 seconds), the left one is close to be cold.
Water flush out the exaust seems good from both sides.
Of course right side has a little bit more water steam...
Is this normal???
Thank you very much

If you can't leave you hand on it it is to hot. Start checking for a restriction in the lines/coolers.

The 2 will always be different, how much different can be an issue. Use a IR temp gun and measure the difference

You might want to verify proper gaskets were used at riser joint. They may have 2 or 4 water passages. Good luck!

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Need more info. Year. OEM manifolds or aftermarket? T-stat and impeller changed? All hoses and coolers flushed. As stated, have manifolds/risers been been checked.

I have noticed this before but never completely figured out why. Why is it AD?

Fluid dynamics, water flows the path of least resistance. So what flows thru one side because its easier and once there is enough resistance from the flow on one side the other side flows. As flow increases it will always have more on one side then the other.

Water comes up from the pump, thru the hose and can for the most part go straight across and out one side of the exhaust, the other side the water has to do a 180 to go out

Only way to get 100 % equal is both sides have to be 100% full

Yours should be like this I think