I just noticed that you have an early gen 5. Many of those have the wrong bypass.

I have a 93 gen v that was giving me the same problem
I was ready to buy a new oil cooler when a local marine engine builder told me not too I went and bought a remote oil filter mount w/thermostat
that is actually for a 540 Bulldog eng and a new block mount from Cp Performance then plumbed it up wiyh 3/4" fitting and #12 hose
as per his instructions
When you look at your remote filter mount you will see that it has very small ports in it less than 3/8 this creates restriction and gives you higher temps
I can look thru my receipts for the part numbers if you like
I now hold it to the stops for 10 min and it doesnt go over 240

here's a couple threads. Good reading http://www.offshoreonly.com/forums/s...hp?t=106633&hi http://www.offshoreonly.com/forums/s...t=oil+bypassng.

Good tips there Patriyacht
can I change the pressure relief valve while it is in the boat or do I have to pull the engine to do it my oil pressure does still drop even though my temp isnt getting as high
Darryl

By the sound of it, the bypass might be the problem. Because I did all the rest of the things suggested such as changing to larger oil line and fittings. I just hope I have no problems installing the new spring.

PS....Patriyacht, thanks for that photo