1988 mercruiser alpha one water pump issue

[Nick2020]

Recently bought a boat with a mercruiser 4.3 and alpha one out drive. It did not pump water at all before. I just replaced the impeller, it is pumping some water but overheating. I took off hose from out drive and it does not really pump any water at idle but when revving it it birps water out and does not seem adequate to cool engine.

I also made the mistake of taking out the old impeller without seeing which direction the new one should go in. I don't know if I put the fins in the right direction. Could it be that I broke the impeller?

 

[Scott Danforth]

when you took the old impeller out, did you find all the missing pieces?

did you replace just the impeller, or a whole pump kit?

at idle, the hose from the transom shield should be shooting about 7-8" up in the air.

 

[jerryjerry05]

The direction of the vanes?? makes no difference.
The impeller is it the same as the one you removed?
They sell one(Force/Chrysler) that is just about the same size and when installed it pumps but pumps poorly.
On the hose or in the water?? The hose might not supply enough water??
You replace the wear plate and the rubber top seal?

 

[Rick Stephens]

Are you sure you got the key back in?

 

[Nick2020]

I replaced everything. I got the whole kit on Amazon for $30. Maybe I got a cheap one that doesn't work well.

 

[Rick Stephens]

Are you sure you got the key back in?

Your symptoms kinda match up to what would happen if there was no key driving the impeller. Hence the direct question.

 

[Nick2020]

It could be I'll have a look

 

[Scott Danforth]

important bits like impellers are things that I would not buy from the cheap vendors on amazon.

I would recommend a quicksilver kit for the raw water pump

 

[Rick Stephens]

To reiterate what Scott said, some parts are best bought OEM Mercruiser - pretty much all rubber parts especially.

 

[Scott06]

Would also check the water tube is assembled correctly, easy to misalign when reassembling the two halves. If it previously over heated the water pocket cover could be damaged

 

[Scott Danforth]

Would also check the water tube is assembled correctly, easy to misalign when reassembling the two halves. If it previously over heated the water pocket cover could be damaged

which is why I asked this question of the OP prior

did you replace just the impeller, or a whole pump kit?

 

[Scott06]

which is why I asked this question of the OP prior

Water pocket cover goes upside down in top of upper and is what the outlet pipe off the pump lands into. It is not included in a water pump kit, but gets melted if it gets overheated good.

 

[crazy charlie]

Recently bought a boat with a mercruiser 4.3 and alpha one out drive. It did not pump water at all before. I just replaced the impeller, it is pumping some water but overheating. I took off hose from out drive and it does not really pump any water at idle but when revving it it birps water out and does not seem adequate to cool engine.

I also made the mistake of taking out the old impeller without seeing which direction the new one should go in. I don't know if I put the fins in the right direction. Could it be that I broke the impeller?

You need to get a service manual and follow it step by step in servicing the water pump.If you are questioning the direction of the impeller vanes ,then you probably didnt push the housing on correctly as you rotate the drive shaft clockwise.Shaft key needs to be installed and lined up correctly.The manual is an easy read and will educate and make sense as it teaches you step by step.Post back where you are at with this.Charlie