I have a Cal 28-2 ('87) with a Westerbeke 13 engine. The engine has always run fine (1700 hours now) and I changed the oil filter and oil about 30 hours ago. The guage for the oil pressure has always read about 30psi at 2700 rpm but happened to read in the manual yest that the pressure should be about 50-75. Do you think the guage is wrong or do I really have low pressure? If it's working fine do I need to address this? Thanks.