Why would water not be getting to the top end of my inboard? It's drawing up into the lower but not up to top

Question

The water is drawing up through the lower. I opened the lower petcock valve and water is pumping out. When I opened the upper, its dry. Could it be an airlock or shot thermostat?

Answer 1

change your thermostat  is the engine running hot?  also your manifolds could be blocked

is the engine fresh water cooled or is it a closed system    if its a closed system the manifolds should be good

Answer 2

Obviously  you  have a broken  or  worn  impeller, which is  located  in the lower unit of  your outdrive, These are  usually  made of rubber  or plastic and  should  be replaced  abopuit   every two  years, If you  fail  to  get water to the  upper  part(  engine) the motor  will overheat ,stall, and eventually seize

Answer 3

By lower pitcock, I'm assuming you are talking about in the engine block. By upper pitcock, I'm assuming you're talking about in the exhaust manifold.???????????????????????

When the water is pumped into the engine by the outdrive impellar pump, it goes through a hose to the thermostat housing. On the thermostat housing there should be three small hoses and one large hose. The other two small hoses go to the exhaust manifolds. Even if the thermostat is stuck shut, water should still be going to the exhaust manifolds. If it was an air lock situation, opening the pitcock would cure that and let the water flow.

SOOOOOOOOOOOO, the problem is obstruction somewhere. Remove the hoses going to the exhaust manifolds and see if the holes in the thermostat housing or manifolds are clogged with corrosion. If they are, you should also remove your exhaust riser elbows to see if they are clogged also. If the riser elbows are clogged, they need to be replaced. If the thermostat housing is clogged, it needs cleaned out or replaced and if the small water inlets are clogged on the manifolds, then the rest of the water jackets in the manifolds are probably clogged as well, but try cleaning them out before replacing the manifolds.

Clogged exhaust riser elbows is the number one cause of engine overheating in inboard/outboard motors , but that doesn't stop water from getting into the water jackets of the manifolds.

Answer 4

hhhmmmm hard question