Are you sure the compression test is correct? How come you have no wet readings? Was the motor warm when you did the test? How do you know that it's running rich at rpm?

If it was running really rich for a long time you could have carboned up your rings.

Test to see if you are actualy running in closed circuit mode and not just on mechanical. When I bought mine the plugs were carbon fouled and the O2 sensor was dead. It still ran fine on mechanical injection but would eventualy have created problems for itself.

Those are really low km's to be worried about serious problems.