1977 Johnson 70 horse

[basketweaver]

I have a 1977 70HP Johnson. I thought that I had fouled the plugs when it wouldn't run full out. I changed plugs and when I first went to full throttle it ran all out. Went back to neutral and started out again and it wouldn't run out, so I thought the carbs were clogged up and cleaned them and it still won't run all out, just goes like your trolling. Any suggestions