Update for Yamaha/MPI turbocharged snowmobiles when using a Roll Over Valve kit
After the MPI air/oil separator drain modification is performed and you are using a Roll Over Valve kit, the ROV shut off valve will need to be relocated in order for the Quick Prime feature to function correctly.
When the MPI/Yamaha drain modification is performed it changes the breather air flow direction. In stock form a majority of the breather air flow escapes out through the outlet (front) port of the separator where the ROV is normally mounted.
After the separator drain is relocated to the engine mag case cover, the majority of breather air flow is now cycling back through the engine.
The Quick Prime system uses this air flow to build pressure within the oil tank and pressure feed oil to the oil pump pick up port.
After the separator drain modification has been performed. Simply move the ROV valve from the front (outlet) fitting on the separator tank, to in-line between the oil tank and separator box.
By relocating the valve after the MPI mod, this will allow the Quick Prime system to build pressure and operate as designed! Attached are a couple of diagrams that I drew up to show breather air flow. The Red arrows indicate high air flow rate, while the Blue arrows show low air flow rate or oil drain back.
Bill
After the MPI air/oil separator drain modification is performed and you are using a Roll Over Valve kit, the ROV shut off valve will need to be relocated in order for the Quick Prime feature to function correctly.
When the MPI/Yamaha drain modification is performed it changes the breather air flow direction. In stock form a majority of the breather air flow escapes out through the outlet (front) port of the separator where the ROV is normally mounted.
After the separator drain is relocated to the engine mag case cover, the majority of breather air flow is now cycling back through the engine.
The Quick Prime system uses this air flow to build pressure within the oil tank and pressure feed oil to the oil pump pick up port.
After the separator drain modification has been performed. Simply move the ROV valve from the front (outlet) fitting on the separator tank, to in-line between the oil tank and separator box.
By relocating the valve after the MPI mod, this will allow the Quick Prime system to build pressure and operate as designed! Attached are a couple of diagrams that I drew up to show breather air flow. The Red arrows indicate high air flow rate, while the Blue arrows show low air flow rate or oil drain back.
Bill
Last edited:
. and it has put me behind on a few things. 
