1983 70 hp Evinrude throttling problem

[river rat]

I have a 1983 evinrude 70 hp. it starts up fine but when I put it in forward gear and give it more throttle it dies out.
If I choke it, just before its starts to die out , it will go ahead on run fine until I slow down to a idle speed and give it more throttle and then it wants to die out again.
I have changed the spark plugs and set them at .30,
I've tried 87,89 and 91 octane gasoline at a 50 to 1 mix and still it dies out.

Any help would be most appreciated.

[Ohioriverrat]

It sounds like your main jets need to be opened up, has it sat with old gas in it or have you been running it all summer and it just started doing it?
you can just remove the 7/16 drain plug in the carb bowl and clean ouut the mains a little, i believe you don't even have to remove the carbs
good luck..