rvd, is there a specific vinegar you should use just for the task of unlocking an engine? I bought distilled white vinegar that is reduced with water to 5% acidity from the grocery store and I am unsure of its ability to do the job. The vinegar is clear like water. I have had kerosene in the cylinders of the engine for almost 2 weeks and it is still froze up. I hope the right vinegar will do the job for it though. I appreciate further info and thanks.