79 evinrude 35hp overheated won,t idle slow

[eastridgebill]

I have a 79 evinrude which recently overheated. I got it running after it cooled down but it will not stay running at about half throttle or less. I was running perfectly prior to that. No discoloration of head however I did get steam and it stalled coming to my boat landing. Changed plugs with new still the same. Can anyone point me in the right direction?? Thanks to anyone who might be able to help.
ps a compression test showed over 75 on both cylinders.