I posted this question on the ask an owner site without seeing this one. This is where I need to be. Two questions: I have a yanmar 3gm30f in our 1987 34 footer. We have the original cast primary filter with a cannister filter insert. On the bottom of the housing is a plug that I took out thinking it would be a separator but found out it isnt.I drained out about a pint of fluid. My filters were changed about 20 hours ago and I dont want to change them right now but may have air in the line because of what I did. Can I loosen the bleeder bolt on top the secondary filter and use the manual pump between the filters to force out any air? Thanks. I am going to our boat tomm. so if you can get back to me thanks. Ques. two. I want to change the antifreeze. I located the drain plug just above the oil dip stick . It has a tube attached to it. First off is this where I can drain most of the fluid? Second, when I loosened the plug to barely a thread nothing came out of the tube. Is the fluid suppose to come out of the tube or will I have to catch it when the plug falls out? And how much approx. will I recover? Thanks.