1998 Johnson Evinrude "EC" 90, 115 SPL Service Manual, P/N 520209, Page 67Get this manual
Pulse Limiter Servicing
[]]The pulse limiter for the VRO pulse hose passes normal pressurevacuum pulsesThe integral check valve in the pulse limiter closes in case of backfire to protect the pulse rectifier valvesTo allow normal pump operation and protect the VRO rectifier valves, the check valve must not be cloggedNotel clogged check valve might restrict VRO fuel and oil
supply, causing serious powerhead damage1Remove the pulse limiter from the crankcase or pulse hose[] 2Inspect inside pulse limiter for carbon and replace valve if excessive carbon is found, or, backflush the valve with OIVK:: Carburetor and Choke Cleaner to remove any carbon deposits Note If excessive carbon deposits are found, the outboard must