Has the 3-point top cover ever been removed ? I replaced the top cover on a M4900 and found alot of cam's and linkage for the draft control, if the cam's got installed incorrectly then you would not have 3-point control. You might try and remove the draft control rod from the top link bracket and move it in and out stopping in different spots, you might gain control of 3-point position.
Paul, June 2009
