Johnson Evinrude Outboard Motors 1956-1970 1.5-40hp repair manual., Page 52Get this manual
POWERHEAD 3-8 TOP SEAL
On powerheads equipped with the heatelectric choke, baffle is installed on the inside surface of the inner plateThis baffle is heated from the engine exhaust gasesAir passing through the baffle heats the choke and allows the choke to open as engine temperature risesCLEANING Clean any gasket material from the cover and inner plate surfacesCheck to be sure the water passages in the cover and plate are clean to permit adequate passage of cooling waterInspect the inlet and outlet hole in the power head to be sure they are clean and free of corrosionThe openings in the powerhead may be cleaned with small size screwdriverClean the area around the exhaust ports and in the webs running up to the exhaust portsCarbon has habit of forming in this areaINST ALLA TION Procedures to install the exhaust covers will be found in Section 3-15, Cylinder Block Service, under Bypass Cover and Exhaust Cover Installation