water pump not sucking up water - going nuts!

[CamaroMan]

howdy all - go an 87 bayliner here.. new water pump, impeller, wear plate.. thought all was good till i get to the water (no pressure from hose).. just zero water getting pushed up from the impeller..

When I had it on the muffs full blast the water would come up to the top hose by the t-stat, when I ran is gushed out - but soon as im on the trailer with drive submerged nothing!

I removed the hose right at the transom before any coolers etc, and still nada - nothing!

Is there a possibility the inlet side of the water pump has a seal between the leg halves or something allowing it to NOT pull water from the grates?

I backed it in about 2-3" above the grates but not fully submerged to test- when I remove the pump and pour water down the inlet port, it streams out the grates but also midway front where the half round anode bolts to the drive - this doesnt seem right - on plane it would suck air..

 

[CamaroMan]

So got it apart - intermediate water tube seals seem good, really cant seem to get why its not sucking water up..

 

[Lou C]

You’re saying the drive was not fully submerged when you tried it in the water? You need to back it all the way down put the drive down and then raise it only as much as you need for clearance at the ramp. Reason why:
Impellers will only pump water not air. On the muffs your water pressure forces water up the water tube which allow the impeller to prime.
in the water when you back down all those passages are full of air! You must lower the drive, this will force water up the water tube to allow the impeller to prime. The Cobra impeller is about 15” above the center of the water intakes...no impeller will pull air and then water that distance!

as far as the connection in water flow there is an o ring between the pivot housing and the drive that must seal and there is a plastic nipple in the pivot (held in with a plastic nut) if this fitting is cracked because the drain plug on the side was not removed it could have frozen.

one thing I need more info on is you said that when you poured water in the openings behind the impeller, water came out the water intakes but also behind the front anode? One passage leads to the water intakes the other leads to the passage from the drive to the pivot housing