9.9 evinrude dropping from high speed

[Wolf359]

Hi all-

I have a 1980 9.9 hp evinrude that I recently aquired. The motor runs great at slow speed but when I open the throttle it will run at high rpm for a few seconds and then drop to low rpm. If I again return the throttle to wide open, the RPMs go up and then down again. Pumping the primer bulb seems to help somewhat but will not return the motor to full speed. Plugs, fuel tank, fuel line and gas are new and the fuel pump appears to be functional. Also, the motor is being run in neutral with the hose attachement. I want to make sure it works before I get it on the water. Any help would be great.

 

[bktheking]

Re: 9.9 evinrude dropping from high speed

There is a lockout that prevents you from going WOT in neutral. Is isn't really a test do determine if the motor is working correctly. It needs to be on the back of a boat to truly test it.

Some checks:With the motor off , check the plastic cam where the roller on the carb rides on to see if it is loose, it's under the flywheel attached to the magneto plate. If it isn't broken or moving it may need a carb service, could be blocked up inside the carb. If the P/O forgot to put a screw back in the magneto plate the cam will wobble but I doubt that's the issue. Check for wear on the roller wheel as well, they can wear a ridge in them, espcially on older motors.