1996 90HP Evinrude Oil Injection

My oil injection tank holds little over 1 gallon. It almost completely emptied out when I just used it for a half day. It was completely full when I started. Motor blowing smoke very bad. Could it be a seal or VRO pump? Big ring of oil in water at dock when we stopped. 

Just got boat back. It was the VRO pump. They replaced with new one and tested it out. Everything good. Thank You to everyone who responded. My motor is not a mosquito sprayer any more.

Thanks for replies. I’m gonna call mechanic Monday. Matt might be right. I had oil tank replaced couple years ago for a bad sensor in tank but have not tested out till last week Boat sat for2 years since I had fixed. Will post results when I find out. 

My 1999 40 hp Evinrude just had the VRO go out. I chose to replace the VRO and eat the cost and not worry about mixing gas.  Same issue you had. One thing to check is the pulse line and gas line to make sure you don't have any leaks that can cause it to use more oil as well and might be a much cheaper fix.  Probably not a seal but you can check your lower unit oil just to make sure and if it has any white streaks in the oil you have a leak somewhere. 

I would lookup how to convert it over to premix / VRO delete. There are multiple kits sold online for little $. 

Got a level sensor in that tank ? My Yamaha vmax did that once  last year when the tank sensor stuck causing the pump to keep running pushing all the oil out the back of the motor, might be as simple as that.