150 HPDI Cooling

[bls-fla]

I have twin Yamaha 150 HPDIs. Both seem to run cool, no sign of overheating. However, I've pulled the boat for other maintenance and saw something I need to check on. While hooked up to a water hose at the flush port, one of the motors has weak streams from the two pea holes above and forward of the water inlet grates on both sides of the lower unit. The upper pea hole, on the motor cowling, has a strong stream and as I say there's no sign of overheating. But it may be a sign of future trouble. I've flushed it twice with Salt Away with no effect, but there must be a blockage. Any suggestions?

[rodbolt17]

they are water pump cavity drains.
they drain trapped water from the midsection and water pump area when out of the water and tilted down.

[bls-fla]

So they really serve no purpose as far as cooling the motor goes. That's a relief, they do drain, but slowly. Thanks for the great info.