I need help with my motor

[derlisserrano]

I have 1981 evinrude 175hp had problem starting problem in the water in the hose start perfect.I check the compressio n have 90 in 4 cylinders on top but 2 in the botton have 70,I don't know how bad it is,all my coils and spark are working good ,put new impeller too.
My rpm gauges is not working either maybe my rectifier is bad I try another gauges an this work can be the gauges,my batteries no charging either .please give advice what do I have to check now.thanks