Impeller replacement after engine overheating - 3.0L Mercruiser

Joined
Nov 16, 2020
Messages
14
Recently, my 1993 Stingray 556 3.0 Mercruiser overheated. It's an Alpha One Gen 2. I suspected it might be the impeller that failed, but when I took it apart the impeller looked pretty good, but the water tube leading out of the impeller casing was toast. It had a pretty significant hole in the tube a little past halfway. What is this called and what is a good part number for it? Is there a kit that comes with the rubber bushing (or is it a gasket) at the bottom? Also, can you ID the metal plate with rubber backing circled in yellow in the photo? Where does that go? Things kind of fell out quickly when I unscrewed the last bolt.

Please take a look at the photos below. I noticed that there were small shells and sand that fell out during disassembly. I plan to blow those out with compressed air. If you think I'm dealing with another issue, please let me know. Thank you in advance for any feedback.

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Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,673
agreed, the impeller is toast

because you ran without cooling water, your exhaust went from 250 degrees to 1000. the exhaust shutter burned up, along with the rubber exhaust couplings.

the plastic guide tube comes in the full pump kit. dont sweat that. you do however need the grommets on both ends of the copper tube as you toasted them. I would also look at the shift seal and the lower unit seal. they have a max temp of 250 as well as that plastic tube did.
 

Rhadley

Petty Officer 1st Class
Joined
Jul 20, 2003
Messages
230
Looks like you sucked up a ton of crud. That would block water flow and cause over heating.
 
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