My outboard is having massive power loss. It started all of a sudden, running down the lake then lost power. It won't even plane out. Before the power loss the motor ran rough at idle and after the loss of power the boat runs smooth at idle but will not plane out. RPM gauge doesn't work buy it seems the rpms aren't high enough.   Open to suggestions.  Wanting to hear what you have to say.

It sounds like you have a Johnson or Evinrude that has a failing power pack/rectifier. Do you get an overheating alarm when it happens?

You are correct on the Evinrude.  Is there a way to test a rectifier, or just have to buy and see. And there is no over heating.

If it is reed induction, one or more of the reeds may have cracked/broken.

I just had the power pack replaced on my Johnson for the same issue.  Motor would run fine and then under load just die.  It would then run rough.  The Power pack for my 150 was $285. With labor etc it came to $391 from the shop.

I might add that it runs like a top now though.  

My older Evinrude 80 was running poorly, wouldn't plane , lugged under wot, idled rough, would surge and or die. Needed a carb rebuild.

Switched parts around and finally figured out a bad power pack on one side.  The motor was running off two cylinders instead of the four.   Appreciate the help guys,  great website