Ed,
195 is on the warm side of normal, but it's still normal. I think in the owner's manual Universal says that the engines should run between 165 and 195. Up over 200 and I'd start to worry, but not at 195. BTW, have you checked the seawater strainer, and/or the thru hull for barnacles?

Since you recently did work on it, it is quite possible you still have an air bubble that needs purged from the system.

Judging from your hull number you may have a Universal 25 engine. I know from my previous C30 that the older models have an undersized heat exchanger. One can swap out for the new heat exchanger (my memory tells me it is 2.5 inch instead of 2 inch) and solve the problem permanently. The 25XP engine always had marginal cooling and everything had to be working correctly to have proper cooling. There was no room for any slight problem.

Oops, I just reread your post and it seems you have the larger heat exchanger.

Try my first suggestion and check to make sure all of the air is purged from the system.

When I had a C30 with a M25 the temperature would go up at higher rpm if the hull, prop and shaft had barnicles. I found in the summer months I would have to clean the bottom, prop and shaft every month and every two months in the colder months.

As far as the heat exchanger on my C36, M35, I had to replace the HX. I had it taken off and cleaned, but the tubes were so coroded it had to be replaced and that took care of that over heating problem.

Ed, I am wondering if your impeller needs to be replaced. I had a similar problem last summer and when I inspected my impeller it was definatley in need of replacing, Of course, then again, it could be that you still have a buble in the system somewhere as others have suggested.

My normal operating temp is just above 160, like 162 degrees.

What Tom said. Check your manual for your engine. Our last boat had an M3-20 and it specified a 195 thermostat and that's what it ran at. The M35A we have now specifies a 160 thermostat and that's what it runs at. I prefer hotter than 160 but I ultimately follow the mfg's recommendations.

With the larger HX these engines should easily maintain 160 +/- a few either way.

195 is not correct and is an indication of an issue. Some "issues" may be;

Over propped (engine must get to max rated RPM with clean bottom & prop)
Injection elbow plugging
Plugged/restricted intake
Plugged/restricted strainer
Zinc crud in HX
Worn impeller
Worn pump body
Dirty HX
Dirty fresh water cooling passages
Impeller parts jammed between pump and HX
Collapsing intake hose (they won't collapse on the pressure side of the pump)
Air in fresh water side of the system
Sticky thermostat
Faulty temp sender or gauge
Undersized intake or too many elbows or restrictions

An infrared pyrometer is the best way to attempt a diagnosis. I would also call Universal/Westerbeke and get the correct flow in GPM at a given RPM for your engine. You then take a bucket and measure how much the pump is passing at a certain RPM. If less than what Westerbeke wants then there is your issue. Many builders GROSSLY undersize engine intakes....

I did a search here and have not seen an actual size for the intake thru hull. Mine just seems rather small from what Catalina has put on and I always wondered if it would run cooler with a 3/4 inch opening or a 5/8 Ours is in Florida and it is only a 1/2 I know.
Randy

Ed, just to clarify...cleaning out the heat exchanger usually does not involve opening up the closed fresh-water pressure side of the engine cooling system. It's usually done on the raw water side only, unless for some reason the HX had to be removed, say. The 'burping' is something that would need to be done only on the closed (pressure) side of the engine coolant system.

the raw water intake is approximately on-half inch in diameter. I had eel grass lodged in the line, Coat hanger did the trick.

Ed, since you're in Ventura I assume you've been boating in the salp-infested waters we've had for the last several weeks. These are the small jellies that float about in chains and singly. On a recent trip to Santa Cruz I. my raw water strainer and intake grate became completely clogged after just a couple of hours' engine use on the back side. Others were experiencing the same problems. I dunno what would happen if one or more of those made it past the strainer; if there's anything they could lodge in and block. Measuring your exhaust water is the only sure way to see that your system is flowing properly, I think.

See you at the islands!

Nick