1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 69Get this manual
Trouble Check Chart (Cont TROUBLE 3LOSS OF POWER (Providing Ignition OK) (Cont) POSSI BLE CAUSE
EOVERHEATING POWERHEADSee Section 4
Thermostats damaged Thermo cover or gaskets damaged Pressure control val ve damaged Exhaust cover gaskets leaking Head gaskets leaking (warped head) (water in cyl inders) Water intakes obstructed Pump housing air bleed restricted Water passages obstructed Pump plate not sealing (bottom) Pump mpell er damaged Motor too high on transom Pump housing distorted (overheating) Pump housing cover seal worn (driveshaft grooved) Water tube grommet damaged FGEARCASESee Section Propeller hub slipping Bent or worn propel Ier Bent gear housing or exhaust housing Incorrect propel Ier ASPARK PLUGSSee Section Cover or inner terminal damaged (terminal point out of HTlead) Faulty leads or crossed leads Loose spark plugs (low torque) Defective spark plugs (cracked insulator) Incorrect spark pi ugs BIGNITIONSee Section Incorrect timingLoose wiring (connectors improperly joined) Coils damaged Arcing around ignition coils Loose connections to sensor coils, charge coils, ignition coils, or on power pack ground lead Leads grounding out on sensor coils, charge coils, ignition coils, or key switch Sensor coi ls Charge coi Is Power packs Arcing in key switch CFUEL SYSTEMSee Section Recirculation hose plugged or pinched Recirculation nipple plugged Recirculation check valve stuck open Recirculation hose not routed correctly causing restriction Manifold check valve plugged or restricted Carburetor dl system has foreign parti cl es in passagesPrime valve seat has foreign particles on seat and will not shut offCarburetor fl oodi ng Fuel pump diaphragm leaking into crankcase Primer bulb check valve not operating DSYNCHRONIZATION AND LINKAGE ADJUSTMENTSSee Section Throttle plate synchronization andor throttle cam pickup ncorrectl set Eng ne dl speed set too low Check these items if engine stalls