Small air bubbles in discharge side of oil pump

[Moose]

As it says my 2012 rmk 800 is getting air bubbles in the discharge lines. Suction to tank has zero. I can idle the sled and manually open the pump and watch the bubbles move into the engine, oil is pumping as it should. Take it for a 1/2 mile ride and have the small bubbles again. I have repeated this 5-6 times and every time small bubbles. Im kinda leaning towards the pump itself but at $5xx dollars for a new one im looking for opinions. Possibly could be the brass check valves on the cases not holding? Anyone know what kind of vacuum they should hold to test them?

Also i tried it without the lid on the oil tank. No change

 

[+SLEDWRECKS+]

Just did this last fall.
Brass checks hold 4-5 psi. Service manual shows any air bubble under 1" is fine. This is for an Axys, but should be the same for the Pro.

 

[Moose]

1” hey? If thats the case im over thinking this. Mine are 3-4 mm

 

[BILTIT]

Vent the tank, either by vented cap or actual tank vent. Its normal but not optimal. I vented my tank and have never seen a bubble since.

 

[+SLEDWRECKS+]

I would prime the pump a few times and see if they push into the case. I don't like seeing bubbles

 

[Rhodesie]

it may be worth replacing the pump. its probably sucking air in through the seal or possibly a small defect in the casting.
something else is if not careful removing or installing the engine its easy to damage the inlet on the pump. hooks on the chassis.
Oil Pump Assembly, 800, Part 1204438
Replaces 1204363,1204095
Item # 1204438
$525.99