1990 Johnson Evinrude "ES" Cross V 88 thru 115, 150 thru 175, P/N 507874, Page 75Get this manual
Vacuum Switch ServicingV6 Models Functional Test 1All electrical connections should be complete and the engine's battery should be connected
2Remove the vacuum switch hose from the fuel pump and connect vacuum tester to the hose
i all spark plug leads
'" To avoid accidental starting of engine, twist and remove
3Turn key switch to ON position
4Slowly draw vacuum on the vacuum switch hoseThe warning horn should sound continuously as the vacuum approaches the switch's preset limitRefer to the chart below for your engine's limit