I took the boat out this past weekend and still have a problem with the starboard engine running hotter than the port. I used a temp gun to get some readings. The starboard thermostat is running about 173 with the temp gun. The port is 165 to 168. The exhaust manifolds are 170 at the back and runs up to 210 at the front. The port engine shows about 160 up to 190.

Another post shows the steps I have taken. viewtopic.php?f=8&t=3764

1) when I winterized the 5 gallon jug I was pulling the antifreeze through took a lot longer to pull through the engine than the port engine did,
2) I treated the engine with Ridlyme and it improved the flow. Still slower than the port engine but thought it would buy me some time.
3) the boat is 13 years old. I went ahead and bought replacement heat exchangers, oil coolers, transmission coolers, and thermostats. I also am going to buy new hoses. Everything I read says that they are probably past their service life.

Questions are:

Are the temp gun readings out of line with “normal”?

Any recommendation on brand of hoses to use? Some will be bought formed, along with about 24 feet of 1” hose for some straight runs. I will probably use wired hose.

Any gotchas involving the heat exchanger to watch out for?

Should I replace the risers and manifolds? (All fresh water use)

If I replace the risers and manifolds, should I buy new nuts and bolts? What is the best stuff to coat bolts with prior to putting the nut on them.

Should all the clamps be replaced or just re-use the old?

Any other thoughts, advice, or suggestions?

Thanks in advance.