Seadoo's oil injection is VERY reliable. BUT... it needs serviced every couple years. If you don't have an issue now... I would NOT recommend removing it.
With that said........ I would:
1) Change the filter in the feed hose.
2) Replace the 2 small injection hoses.
3) Verify that the nipples at the manifold are clear.
4) Verify that the check valves are clear.
Once that's done... bleed the system, and you will have a visual check that the system is running.
Normally the only reason people have an issue with a seadoo oil system, is because it was never serviced, and either the filter gets plugged up, or the small oil lines rot, and fall off.
Last thing... since your SPX has a rotary valve... even if you go Pre-mix... you have to leave the oil tank in the hull, and hooked to the rotary valve gears in the center of the engine case.
