1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 108Get this manual
7 The tests in Step indicate the VRO unit is operating normally and the variable ratios are within specifications8If the VRO unit fails any of these tests, check the pulse hose fitting before replacing the VRO unit9If you replace VRO unit, be careful when removing or installing the hosesDo not damage the plastic hose fittingsUse ratchet style clamp on the oil supply hoseTorque the screws, VRO -to -bracket, to 18-24 inIbs(2-3 Nm)Refer to Hose Routing Chartthis Section INote When installing oil supplycould cause serious powerhead hose, be sure connections are airtightPoor connections
damagePulse Hose Fitting
The crankcase fitting for the VRO pulse hose has an integral flame arrestorThe flame arrestor is not serviced separately, but must be clean to allow normal VRO operationA clogged flame arrestor might restrict VRO fuel and oil supply, causing serious powerhead damage 1Remove the pulse hose fitting from the crankcase