1993 Pro v 150 started running rough, so i checked the compression and it was good, but noticed i had white milky stuff on plugs (figuring it was water) i took heads off and the head gaskets was bad and had alot of corrosion. So got them changed and put new plugs in and took it out, ran great for about 200 yards honestly better than it has in a while. But then it started cutting out, i was guessing water was getting back on the plugs, but i hit the choke to make sure and it made no difference. So came home checked compression again and it was good, but looked like a couple plugs had really clean spots on it. Im suspecting maybe a bad water jacket gasket? would appreciate any help. thanks guys