Started working on a 79 Honda PA50I with my son. We noticed that at the upper end of the throttle, 4 stroking was beginning and the top speed was about 15 mph. So we followed directions listed in the forums here (which were a huge help!) and dropped the engine, took apart the carb and cleaned everything we could find. Checked and cleaned the air tubes and repaired the sticking choke.
Put everything back together and it started right up. Here are the problems:
When trying to set the idle speed ( after it warmed up) the best idling that we could achieve was with the air adjustment screw all the way in.
Now when we start the engine, it idles OK, but when we attempt to increase the throttle, it starts to speed up but then sounds like it floods and will stall if we don't decrease the speed to idle.
Pulled the spark plug after trying to run the engine, very black. We are running 25:1 mixture as per directions.
Tried spraying starting fluid around the engine and carb with it running, but no increase in speed at all.
Frustration is starting to set in. We are not thrilled about dropping the engine again ( it was so much fun the first time!)
Question about the attached carb picture. What is the disc located just below the air mixture screw? When I was cleaning the carb, and utilized compressed air, I would see several bubbles when air was pushed through the air mixture screw hole.
Any help that is available would be much appreciated. Sorry this is so long.