You could have a larger issue in general. Any WVO that has deposited in the piston ring land area will turn into a glue and stick the rings. If the engine is out of service for a long time. This may or may not have to be addressed. There are two potential problems in the injection pump. It is worn from WVO use or the moisture content of the WVO was too high. Neither are certainties.

So how long did the engine sit unused?