Home › Forum › Ask A Member › any harm in back flushing ’67 Johnson 100 hp? › Re: any harm in back flushing ’67 Johnson 100 hp?
September 28, 2015 at 12:21 am
#24731
There is supposed to be a spring loaded bypass in that thermostat housing along with the thermostat, the engine won’t cool properly if those items are missing as well.