Re: Honda BF 50A (2000-2001?) Cooling System Not Peeing (Mud Bugs)
I've recently gone through this process with my Johnson kicker (i have a Honda main engine). Although your engine is different, there are several common areas where you might find a solution.
I used water from a garden hose - forced up the water uptake tube. If water is coming out anywhere, you can see it.
Check the top of the water uptake tube. there is a rubber grommet/fitting that can get out of position and block flow. If this is where the blockage is, you may have to remove the power head to get at it.
You could also try to poke weed-eater line up into the tube in case a blockage can be dislodged.
Find the thermostat housing (Maybe someone else can advise location of yours, or search on-line parts diagrams) Remove the cover. It's a common place for gunk to accumulate. With water forced up the uptake tube, it should flush out debris through this location.
You can check the thermostat while you have it out. (heat it in a pot of water to make sure it opens correctly) Mine was badly corroded & questionable, so I put in a new thermostat kit.
You didn't mention the tell-tale. You could use air, water, or weed-eater line to check/clear blockage.
Others have recommended removing the exhaust plate to check water passages underneath.
The blockage in mine was in the tell-tale section. The rubber hose from the block passes through the carburetor housing, through a 2" passage in the aluminum - this section has a smaller inside dimension than the hose and it was totally plugged with salt/crud.