Re: waterflow throuh an FD model Johnson 18-20 hp
Re: waterflow throuh an FD model Johnson 18-20 hp
Neither picture is correct. Water follows two paths through the powerhead. Only one path is thermostat controlled.
First path is up through the hole next to the thermostat, across the cavity and down thorough the hole on the right. That path is always open.
Second path is up through the hole the thermostat sits in and down through the hole on the right. That path is cut off when the 'stat is closed, except for a small bypass notch in the 'stat. The 'stat element is thus bathed in the water to sense it's temp, and opens when it is warm enough.
First path cools the exhaust cover, and part of the cylinder head, and is discharged into the exhaust housing to cool it. Those are the hot spots that require constant cooling.
Second path cools around the cylinders and the rest of the head.