Reply To: 1967 sportwin 9_1/2 hp

[need2fish]

Further to Crosbyman’s comment about exhaust gases — there is a large rubber seal at the bottom of the exhaust cavity and it tends to rot and leak over time. That will definitely affect the low speed running as the engine aspirates the exhaust. In some cases water gets past it and rusts the lower crank seal.  At high speeds the exhaust is siphoned off and the engine runs smoothly . There is no replacement for the exhaust seal.