290 hours. 502 MPI, low oil pressure and high temp. For example, 3000 RPM, 20 lbs oil pressure, 210 oil temp. Other motor 40 lbs & 190. I believe old rule of thumb 10lbs for every 1000RPM? So last week changed oil, raw water pump and found semi clogged line coming thru transom. Removed and replaced ( pulled drive to do so). Ran great for one day, next day right back to above. Any input appreciated. Thanks

Bravo fever?
On the inside transom plate the opposite side you worked on. Where the inlet water elbow mounts to the transom plate. Pull the elbow and make sure the hose (the one I assumed you pulled to replaced your hose) is not collapsing. Sort of a bear to get to but once off a mirror and flashlight might be your best way to go to see.
Or check the oil cooler for debris.
20 psi at 3000 is quite low, main bearings? cam bearings? a multitude of things?
Did the pressure come up after the oil change?

The pressure did come up after the service, but after one day was back to where it began (20lb)... I'll take a look at the hose you suggest and value your feedback. Thank you