I have a 1956 model Super 55 with a low oil pressure reading on the guage.I have used another guage to verify that i don't have a bad guage.The engine is stong running a i have used it enough to be confident that its okay.The guage reads less than 10lbs at all times reguardless of cold or hot engine.I have checked the pressure regulator for a broken spring or a stuck plunger but, it checks okay.I have heard that underneath the oil filter there was a restricter washer or something that sometimes was lost during a filter change.My tractor does not appear to have this item under the filter.Just a round hole about 3/8" in diameter.Does anyone think this is my problem? Maybe Mr.Schwibert? Thanks.