1994 Johnson/Evinrude Outboards 40 thru 55 Service Manual, Page 80Get this manual
Disassembly 1Remove primer pump housing retainer from primer pump II!] 2Remove primer plunger from
Inspection
Discard O-rings
r:;J Inspect brass plunger shaft for any burrs or scratches
Remove small scratches by polishing the plunger with crocus clothIf the plunger has deep scratches, replace the plungerInspect plunger where cross hole intersects inside holeAny burrs around cross hole will accelerate wear of O-ringsRemove any protruding burrs, and polish with crocus clothThe check valve under the small nipple on the primer pump housing allows fuel flow out of the pump housing and prevents flow into the housing
I13l To verify check valve function, connect clear plastic hose
between the small nipple and syringe filled with isopropyl alcoholSqueeze the syringe lightly to force alcohol through the hoseVisually check for alcohol flow into the housingIt is permissible for few drops to enterThis indicates the check valve is blocking the flow and functioning correctlyIf steady stream of alcohol flows through the small nipple, the check valve is inoperative and the primer pump housing must be replaced