1997 Johnson Evinrude "EU" 90 thru 115 90 CV Service Manual, P/N 507267, Page 65Get this manual
Pulse Limiter Fitting
[] The pulse limiter fitting for the VRO pulse hose has an integral check valveThe check valve is not serviced separately, but must be clear to allow normal pump operation INotel clogged check valve will limit fuel and oil supply, causing serious powerhead damage
1Remove the pulse limiter fitting from the crankcase[] 2Backflush the valve with avK:: Carburetor and Choke Cleaner to remove any carbon depositsI Note If you find excessive carbon deposits, check the engine for causes of backfiring:
Linkage adjustments incorrect Engine temperature incorrect Crankcase air leaks Carburetor problems Extended use of flushing attachment
3Clean the threaded portion of the fitting and apply avK:: Pipe Sealant with TeflonInstall the fitting, and secure the pulse hose with clampPump