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1990 Mercury 4hp impeller removal issue. Lower unit does not want to come off.

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ktmarty

New member
I have a 1990 Mercury 4hp and need to replace the impeller.

After removing the two bolts from the lower unit I try to remove the lower unit, the gear shift is in neutral to start out as the lower unit is moved the gear shift goes into reverse and the then lower unit stops (~three inches) just enough to see the impeller. I tried moving the shifter into reverse then move the lower unit off but stops about three inches and will not come off any further. Tugging does not help or giggling the gear shift. Any ideas?

I seen video and theirs come right off with no issues.

Thnx

Marty
 
You have to disconnect the shift shaft. There is a rubber grommet just above the lower unit. Pop that out, and you'll see the bolt. 10mm by the way in case you're wondering.
 
LSXG8GT said:
You have to disconnect the shift shaft. There is a rubber grommet just above the lower unit. Pop that out, and you'll see the bolt. 10mm by the way in case you're wondering.
Click to expand...

Thnx that did the trick.

I just bought this Merc knowing the impeller was not working. It looks like the impeller is in great shape. I blew out all the holes in the impeller assembly that I could find to make sure no blockage even the little pin hole where the impeller case goes over. I also blew out the line that goes back into the engine case where the water spits out . Any other ideas to look for?

Marty
 
With the lower unit off the engine (if you still have it off,) blow compressed air into the tell-tale, and you should hear air coming out of the water pick up tube (copper tube going from your water pump to the power head.) If you have air, then I would just install the lower unit and run it in and see how it pumps.
 
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