1997 350 Overheating

I have a pair of 350 inboards in a Pursuit 2800, 700 hours.
I changed impellors,thermostats and new belts. Both engine runs at 180-185 at 3000 rpm, increase to 3500 and the port engine gets up to 195-200, using a heat gun. On the hot engine,the port riser reads abour 20 degrees hotter than the starb. side, just touching them and I can feel the diiference. Water flow seems OK. Water does come out of the hot riser. If it was partially blocked would the engine overheat? There is water flow out of the hot riser,I plugged off the other side and water flowed out the exhaust.

One riser is partially plugged, as you surmise, but that won't make the engine run hotter. Look for an air leak before the raw water pump. The tiniest of air leaks will cause exactly what you're seeing 'cause aerated water does a poor job of cooling, especially when you throttle up.

Jeff

Thanks for the reply, I will be on the boat today and check all my hose clamps etc. and see if I can stop any air leaks.

Bryan