Port engine temperature at 155 degrees rather than usual 175 degrees

[340DA]

The temperature of my port engine of my 2000 340 Sundancer is actually running (lower) at about 155 degrees. Both Starboard and Port engines usually/typically are in sync at 170-175 degrees each. However, the port engine warms up to be running lower than usual, at 155 degrees. Stbd is still at 175.

I have a 7.4L mercruiser with Bravo 3 outdrives. I cleaned the barnacles off of the water intake on the outdrives and any that were around the props. Port is still at 155

After this, I'm thinking it's either thermostat issues or something else???

Any suggestions to help diagnose and/or resolve this issue?

Thanks