I have a 1982 70hp johnson seahorse outboard. I have owned it for 2 yrs and never had a problem with it until now. It runs fine for about 20-30 mins untill it warms up. Then it bogs down and has no power. But still seems to idle fine. If i let it cool down a while it will run fine until it warms back up. I brought it home and ran it with the water hose and it seems to run fine. Any Suggestions and help would be greatly appreciated.