The ski sank in salt water and although I did a extensive cleaning I now have very low compression on all cylinders. (Less the 100 PSI) I am in the process of removing the head but ran into bolts that I cannot loosen due to corrosion I guess. Valve train rocker bolts and head bolts/Torx. (8mm and 11mm) I wanted to remove the head to clean further and view the valves and cylinders. Any help would be appreciated.