I see that the 500 and 550 are almost the same. The 550 can give error codes from the dashboard, I don't think the 500 can, not the same dashboard. . Trying to find out why the motor is losing power/fuel and need info on parking brake replacement.
All the info in the 500 files are for carb motors. I am thinking that not many 500's were made before they switched to the 550.
I like to do my own work, but hard to do it without good tech info