1990 Johnson Evinrude "ES" 9.9 thru 30 Service Manual, P/N 507871, Page 93Get this manual
Intake Manifold Servicing, 20-30 Removal 1Follow steps listed in Carburetor Removalthis section
2Remove pin
end of throttle control rod
3Remove tie strap and disconnect oil recirculation hose Remove nuts and screws attaching intake manifold to powerheadRemove intake manifold and gasket
5Remove flat head Phillips screw leaf plate assembly and gasket
and carefully remove
Inspection
INote them solift or they may not seal by handor may break after Do not bend leaf valves This may damage that properly
the engine is returned to service1Inspect the leaf plate assemblies for damage: The leaf valves and plate must not be distorted The leaf valve tips must not be cracked or chipped The leaf stops must not be distorted or loose Use machinist's straightedge to check the flatness of the leaf plateThe gasket surfaces must be flat 0.003 in( 0,08 mm)