1997 Johnson Evinrude "EU" 40 thru 55 2-Cylinder Service Manual, P/N 507265, Page 70Get this manual
Primer System Servicing Function Test
1Start engine and allow it to reach normal operating temperature Set engine speed at 2000 RPM2While engine is running:
Electric start modelsPush key inEngine should run richly and drop 1000 RPM
Manual start modelsStroke primer knobEngine should run richly and drop 1000 RPM
3Remove primer hose from any primer fitting that you suspect is cloggedConnect 18 inI.Dclear vinyl hose between the fitting and syringe filled with isopropyl alcohol4Press lightly on the syringe plunger If fluid moves through the fitting, it is okay