my neighbor got a 1977 35hp Johnson that had been sitting for 2 years. when I run it in a test tank, exhaust fills up under the hood and chokes the motor out. any ideas what might cause this?
Yep, you're running it in a test tank, that's what causes it. If the problem persists on a boat, then you have a problem, but in a test tank, a strong fan directly in front of the motor to blow exhaust out of the way is necessary.
