This weekend I purchased a 90hp Johnson, for $300. My plan was to rebuild it and keep it as a spare, it has 100-110psi in 3 cylinders and about 20psi in the 4th cylinder. This motor was an obvious saltwater motor, is it going to be as hard as I expect to get this thing apart to find out the cause of the low compression? motor seems to run very good other than the bad cylinder. any tips to aid getting the bolts out without breaking them would be great.