Oil & Fuel Low Oil Pressure in Jinma 304

[ALMike]

I've got a 2003 Jinma 304, with 430 hours on it. The oil pressure gauge has always registered just above the red zone, but yesterday it started straddling the red zone on the factory gauge.
Any tips for what I should do to troubeshoot this? I'm thinking about replacing the original chinese individual oil pressure gauge, what kind of oil pressure reading should I see in lbs at idle vs. full throttle?

 

[Soundguy]

I'd slap a mechanical gauge on there before I started it again.. then go from there.

See what your REAL oil pressure is from cold to hot, idle and throttle.

keeping oil changed correctly? not fuel diluted?

soundguy

 

[Diamondpilot]

Like Soundguy said you can buy a test gauge at Harbor Freight or do like I did and bought a cheap $10 gauge with all types of fittings at Auto Zone. I have used it to check oil pressure on my tractor and many other engines in boats to cars.

I really doubt its the oil pressure gauge. The sending unit has been a problem area on some tractors including mine. I started 1 day and no oil pressure. I called one of the dealers, I think it was Ronald at Ranch Hand, and he told me to check the wiring and the stud that the wire connects broke off in my hand. Guess it got slapped with a limb or something. He said to take the sending unit out and with the fuel cut off pulled crank the engine to see if it pumps oil which it did. I put it back in and worked the tractor for 3 days while I waited on a replacement. That's when I got the mechanical gauge at AZ to do a test.

I think the old rule of thumb is 10 psi or so per 1000 RPM. I think on my tractor it was somewhere around 7 psi at idle, about 600 RPM, but would not swear on that. This is warm test.

Chris

 

[GuglioLS]

For sure get a second opinion gauge. There is a pressure relief adjustment built into the oil filter assembly. Look for a cap nut, remove the nut, underneath the cap nut there should be a screw, screw it in and see if the pressure goes up. The oil pressure on my 354 when cold goes right to ~ 70 PSI no matter what RPM. After it warms up and I mean at full operating temp, the pressure will vary from about 40 PSI at 600 RPM and right back up to 70 PSI @ 2000 RPM.

Larry