Maybe over thinking

Then you have to do more trouble shooting as to why the engine is not performing.

Raceone I feel your frustration as I am.living it. But I think something has come up. I did and do get spark at idle on all 3 cylinders not sure when at full throttle but still sounds smooth. What I noticed when the head was off is that number 3 or bottom pistion was still silver where the other two were black. I have to assume maybe number 3 is losing spark??? I had cleaned the pistons prior to any photos. Know that we confirmed pistons are in correctly ( two ports face the flywheel) there must be something as to why two.pistons were black and one silver.
Thanks for the help.

Did you replace the 3 gaskets on the exhaust manifold ??

Yes all new. One black on the block the 2 green

Hinall results of another tear down and rebuild. Over looked something that I was not aware of. When I purchase this boat and motor it had been repaired with evinrude parts including the gear box. What effect does that have I believe the ratio is 2:1 where I think mine is 2:65. I installed a much smaller prop and it easily hits 3500 tp 3600 now from 3000.

Evinrude and Johnson parts are the same !-----There is something wrong with your tachometer.----Or with your motor.-----Gear ratio on the 3 cylinder 60 / 70 HP has always been the same 12:29 or .41 as far as I know.

After reading through this long tale of woe, post #32 finally grabbed my attention. A clean piston is a sign that it might be ingesting water into the cylinder, "steam-cleaning" the piston. I'm pretty sure that also was racerone's thought when he asked the question in post #33. Warped exhaust parts may leak, even with new gaskets. Do we know what caused the original damage to this motor? Overheated, maybe?