pumps when tilt up but not when down???

[Triangleboater]

good morning!

So I have a new to me 3.0 mercuirser with the alpha 1. I did all the proper new to me things following the factory manuel. Water pump kit, lower unit oil, greased splines, hoses, thremostat, etc.

So my issue is, it won't start pumping water until i trim the stern drive up almost all the way (to trailer mode). Once I do that it will pump water all day, up, down, however I trim it. If I start with the unit down it won't pump water. This is the impellar in the lower unit I am speaking of, not the circulation pump on the engine.

I am doing this with dual side flow muffs on the hose. I have not tired it with the boat in the lake as I am finishing up some gel coat repairs.

The engine purs like a kitten!!!

I thank you in advance for any help!!!

 

[Bondo]

Ayuh,.... There's a hose at the transom that the in-comin' water runs through,...

My guess is, it's kinked,... It has to be "Just So" when the clamps are tightened or that can happen,...

 

[Triangleboater]

Is that on the inside of the boat at the transom or at the sterndrive where it meets the transom?
Thanks for your help by the way!

 

[Bondo]

Is that on the inside of the boat at the transom or at the sterndrive where it meets the transom?
Thanks for your help by the way!

Ayuh,.... Up in under the drive, outside the transom,...

 

[Triangleboater]

You don't have a picture of that do you? or a diagram that spells out where I look? I went out and looked during lunch and couldn't see where you are speaking of.

 

[Bondo]

You don't have a picture of that do you? or a diagram that spells out where I look? I went out and looked during lunch and couldn't see where you are speaking of.

Ayuh,.... With the drive trimmed All the way up, lookin' Up from the ground, there's 2 big bellows, a small bellows, the shift cable, 'n the water hose,....
All right between the drive, 'n the transom,....

You said ya got a manual, look under bellows replacement,....

 

[Triangleboater]

So I went ahead a replaced the bellows, including the water hose and oil hose (did gimble bearing too). What a job...
Anyway. I am still having same problem. The hose isn't kinked. I am thinking the problem is in the impeller area?????
Could it be the connection where the pump meets the tube going up into the out-drive? I am thinking I replace that plastic piece and the o rings and go from there.

Any opinions?

 

[UncleWillie]

Nothing in the drive above the impeller moves relative to anything else when tilting.
If the plastic pipe in the drive didn't land correctly you should be spraying water out the prop even if the engine is running dry.
On Muffs, you might even have water out the prop with the engine OFF.

When you say that "it isn't pumping water" is that because the engine is getting hot, or you just don't see water coming out the prop.
If the block drains, it will take 30-60 seconds to refill before any water appears in the exhaust; About the same time it takes to Trim up and down.

 

[Triangleboater]

No, the engine is getting hot 200 degrees or so (always shut down if it gets close) and I also, took the hose that comes in from the outdrive off the thermostat housing and no water is coming in. The problem is with the raw water impeller.

I did notice that is now, after replacing the bellows, is only pumping at random times, doesn't matter if the drive is up or down (trimmed).

I am beginning to think that the woodruff key (or whatever the key is called that holds the impeller on the driveshaft is somehow only turning the impellar at random times....

Could that be the case?

 

[Triangleboater]

also, no water is coming out of the prop so the connection with with the top of the pump and the tube going up the outdrive must be ok.

 

[Triangleboater]

bump

 

[Alumarine]

I think you'll have to split the drive and check out the impeller and maybe the water pocket cover if that applies to your drive.

 

[Bt Doctur]

remove the drive and insert a hose into the water inlet and post the results

 

[Triangleboater]

Water pocket cover? What is and where is that? also, before I did the bellows I did put a small hose of the water inlet and it went up fine.