Yamaha L4 3.0 coolant water blockage in stern drive

[rdoty]

I'm in the process of restoring a 1990 Ebbtide 170 XS with a Yamaha L4 3.0 stern drive. I finally got the motor running today but discovered that there is no coolant water. By process of elimination, the problem seems to be some kind of blockage within the stern drive unit itself. I've disconnected the hose that runs from the transom mount to the seawater pump and the hose is bone dry although the flusher is supplying plenty of water. I've got all the Yamaha manuals, engine and stern drive, but there's nothing showing the coolant water path through the lower unit and transom mount so I have no idea where to look for the blockage. Does anybody have a clue as to what or where the blockage could be and do I need to remove the lower unit to access the coolant water path?

 

[Bondo]

Ayuh,.... Welcome Aboard,..... There's the hose from the transom, the fitting it attaches to, another hose from the transom to the drive, 'n a tube in the drive down to the water pickup at the lower unit,.....

I'd pull the drive, 'n see what's goin' on,.....
Bein' on the vacuum side of the pump, it could be an air leak, rather than a blockage,.....

 

[rdoty]

Ayuh,.... Welcome Aboard,..... There's the hose from the transom, the fitting it attaches to, another hose from the transom to the drive, 'n a tube in the drive down to the water pickup at the lower unit,.....

I'd pull the drive, 'n see what's goin' on,.....
Bein' on the vacuum side of the pump, it could be an air leak, rather than a blockage,.....

Thanks for the response. I did resolve the blockage issue by pushing a 1/4 OD tube connected to my garden hose up the water inlet of the lower unit (removing the strainers first). At first it would only go about six inches but when it finally broke through it was maybe 8-10 inches. Not sure what the blockage was, probably fine sand, but I'll do a major flush before I reconnect to the seawater pump.
I'll post for another issue - the trim/tilt pump