Avanza

Hi all. I have a 79 Mariner 40BE, 676Bs 101893 While the motor is running there is a milky white substance leaking from one engine mount alot and just a dribble from the one on the other side. Since I have no idea when the last maintenance was carried out on this engine I've decided to pull it down and replace most gaskets, impeller etc. I have removed the lower unit, outer exhaust cover, head gaskets and seperated the power head from the midsection. Many words were said that can not be repeated on this forum due to the terrible state some of the bolts were in thus snapping them. Have drilled the bad ones and retapped them they should be good to go. My question is though is there some kind of seal inbetween the top of the midsection and the bottom cowling or will a new gasket inbetween powerhead and exhaust solve this leak. I have not yet taken the midsection off as it looks complicated. If need be could I get some help on what is the best way to remove the midsection. Regards Brendo