Totally baffling !!! Impeller replaced !! And not pumping

[kinger952]

ALPHA 1ST GEN Second new one with all housing parts and o-rings & gaskets and dunked in large tote full of water made a custom socket to fit in 1/2 " variable speed Dewalt drill spun both directions and NOTHING !! BY LOOKS OF THE BRASS IN THE IMPELLER THE KEYWAY DOESNT SEEM TO BE SPINNING
I'm at a loss I've done dozens of these with ZERO issues till now .
All water pathways are clean and clear .
Enclosing 2 pictures 1 of old imp and 1 of new

 

[Rick Stephens]

Hook it up to muffs and try it. If you dunk, you gotta get the pump completely submerged.

 

[kinger952]

It will pump with muffs on but there is water pressure there . This is a 30 ft twin engine .
Starboard engine pumps/lifts like it should from tote /port engine is the one fighting me - why would one lift and pump and the other not ?
Both lowers got new impellers but port is fighting me

 

[Rick Stephens]

A Mercruiser Alpha drive, either Alpha 1 or Gen II, cannot LIFT any water. Not ever. That impeller is vented to let air out when submerged. If you look at the base there is a slot cut all the way through to allow air to escape which is how the pump primes. No such thing as lift or suction with this type of pump. It just sucks air when it isn't fully submerged.

 

[kinger952]

Well I'll check it out in the morning I guess .
I DONT want To be one of those idiots at the launch that ties everything up !!!
Thanks

 

[Bondo]

BY LOOKS OF THE BRASS IN THE IMPELLER THE KEYWAY DOESNT SEEM TO BE SPINNING

Ayuh,..... Sometime ago, there was an issue with the brass drive collar, delaminatin' from the rubber impeller,.....

 

[kenny nunez]

Is the gasket that goes between the bottom of the wear plate and the pump base stuck under the plate? I do not see it in the picture.

 

[kinger952]

Is the gasket that goes between the bottom of the wear plate and the pump base stuck under the plate? I do not see it in the picture.

Yes new gasket is there just not in pic also missing o-ring for bottom of base housing

 

[kinger952]

Ayuh,..... Sometime ago, there was an issue with the brass drive collar, delaminatin' from the rubber impeller,.....

Yes I remember that and nope it is solid -that's one of the 1ST things I looked at

 

[kinger952]

A Mercruiser Alpha drive, either Alpha 1 or Gen II, cannot LIFT any water. Not ever. That impeller is vented to let air out when submerged. If you look at the base there is a slot cut all the way through to allow air to escape which is how the pump primes. No such thing as lift or suction with this type of pump. It just sucks air when it isn't fully submerged.

Not to argue but why does other engine draw water up when impeller is not submerged ?

 

[500dollar744ti]

Is one engine counter rotation?

 

[kinger952]

Is one engine counter rotation?

No it is not
I don't see where that would make a difference seeing how the veins on imp will move into correct direction ?

 

[500dollar744ti]

No it is not
I don't see where that would make a difference seeing how the veins on imp will move into correct direction ?

It sounds like you might need to re-examine the way the gaskets and plate are sandwiched then. I've made the mistake of using one of the wrong gaskets before and that was the problem. Since you have the lower unit off, why not just take it apart, start over and re-install everything after examining it all? Or did you try that?

 

[Rick Stephens]

Not to argue but why does other engine draw water up when impeller is not submerged ?

Just lucky I guess. You will burn up an impeller with the practice. It is almost impossible to meet the requirement to immerse the drive several inches above the pump to get enough water flow to operate safely.

 

[kenny nunez]

If the lower unit is still off use a garden hose to back flush the incoming water to check if anything is stuck in the system. Have you checked if there is anything inside the inlet of the thermostat housing?

 

[Scott Danforth]

It will pump with muffs on but there is water pressure there . This is a 30 ft twin engine .
Starboard engine pumps/lifts like it should from tote /port engine is the one fighting me - why would one lift and pump and the other not ?
Both lowers got new impellers but port is fighting me

stop trying to pump water from a tote. if it works, you are lucky. these pumps are flood to prime, meaning the water level must be 6" or more above the impeller or use muffs.

to get water 6" or more above the impeller, the boat must be in a tote big enough to get the drives submerged.

 

[kinger952]

It sounds like you might need to re-examine the way the gaskets and plate are sandwiched then. I've made the mistake of using one of the wrong gaskets before and that was the problem. Since you have the lower unit off, why not just take it apart, start over and re-install everything after examining it all? Or did you try that?

Lol. Tried that also watched numerous videos even though I have done MANY of these

 

[kinger952]

stop trying to pump water from a tote. if it works, you are lucky. these pumps are flood to prime, meaning the water level must be 6" or more above the impeller or use muffs.

to get water 6" or more above the impeller, the boat must be in a tote big enough to get the drives submerged.

I have a huge tote. If I dunk the unit TOTALLY with a copper pipe coming from pump housing the water should shoot out correct. ?

 

[Scott Danforth]

I have a huge tote. If I dunk the unit TOTALLY with a copper pipe coming from pump housing the water should shoot out correct. ?

you are just dunking the lower unit? then yes, if you could spin the shaft about 300 RPM, water would flow up

 

[kenny nunez]

It just occurred to me what you posted on #18. Are you trying to install the lower with the copper pipe in the top of the pump housing? There is no way the pipe will go in the pocket cover without damaging the grommet.
Even if you are installing the lower with the pipe in the pocket cover there is a chance that the pipe missed the guide tube. Are you raising the lower when the drive is tilted all the way up?
Out of all the times I have raised the lower to the upper I can remember a few times where the pipe missed the tube. Of course I caught it right away when there was no warm water coming out the propeller after a few minutes.
So, put it back together with the drive fully tilted and with someone watching the copper pipe engage the guide tube. And of course being sure the shift splines line up.