I have a 1994 Hunter 40.5 with a Yanmar 4JH2E. Engine runs great, starts immediately when the key is turned on, no smoke on running, even at high rpm.. When the key is off, the oil pressure light in on and the alarm sounds as it should. The oil pressure indicates at the low end of the green range when running at cruising rpm (2200 to 2800 rpm). When I increase rpm, however, the oil pressure decreases substantially. The oil pressure alarm does not sound though. I want to check the actual pressure using a mechanical gauge. I wouldn't mind having a T type fitting so I can put the mechanical gauge down at the regular oil pressure sensor point and still have the electronic sensor installed. So I have a couple of questions.
1. Does anyone know what size/type of fitting would be necessary to install. Size and type of thread to be compatible with the sensor port on the engine? (NPT or straight thread and size, etc.) If you have done this do you have a picture?
2. Recommendation for an mechanical oil pressure gauge to use
3. Does anyone have any thoughts on why the oil pressure would decrease at higher rpms rather than increasing. I am thinking it might be the oil pressure relief valve that is a part of the oil pump/filter assembly.
Inquiring minds want to know?
1. Does anyone know what size/type of fitting would be necessary to install. Size and type of thread to be compatible with the sensor port on the engine? (NPT or straight thread and size, etc.) If you have done this do you have a picture?
2. Recommendation for an mechanical oil pressure gauge to use
3. Does anyone have any thoughts on why the oil pressure would decrease at higher rpms rather than increasing. I am thinking it might be the oil pressure relief valve that is a part of the oil pump/filter assembly.
Inquiring minds want to know?