Alpha I Impellor kit Question

SloBurn

SloBurn

Active Member
May 30, 2013
842
Greenwood Lake, NY
Boat Info
1994 270 Sundancer. 7.4L Merc. Tow with a 2006 Dodge RAM Hemi
Engines
340 HP Merc 454 c.i.
Ok, I've replace dozens of impellors and the last few I've seen, the plastic pipe that carries water from pump housing has been melted due to overheating. SO, I'm thinking about using my own piece of pipe. Stainless steel in place of the plastic that melts all the time. Currently my boat overheats when I'm idling, a sure sign that my plastic pipe is melted to some degree. Anybody ever try this?? untitled.jpg
 
The plastic pipe is just a guide sleeve. There should be a copper pipe that goes from the water pump to the upper unit.
 
I've not seen a copper pipe on an Alpha, at least the ones I've worked on, although I have seen them on an Evinrude......
 
Yes there is a copper pipe, seen on every alpha drive I have serviced. Why not fix the overheating issue?


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The plastic is just a guide to align the copper pipe. Nothing in that section of the drive should be hot as it is constantly pumping cool sea/fresh water . If it is hot there is another problem. Hot engine water doesn't go near that part of the drive, there is another problem causing heat...and that is for someone smarter than me to figure out.
 
I just serviced mine for the first time and it has a copper pipe. AFD makes a good point. You may have another issue. My housing was also melted but I found a bearing issue with the drive shaft.
 
So this is actually the third impellor I'm replacing on 3 different boats this season, and they are all missing the copper pipe! I think because exhaust gas goes down through the drive at this point, it can get hot enough to melt the plastic. I'll know more this weekend..........Thanks all for your comments.
 
If the copper pipe is missing then the cooling water from the water pump can't get up through the upper unit to go through the bell housing and transom to cool the engine. Might be the overheating issue? Most of the time the pipe stays in the upper unit when you remove the lower unit so unless you look up there maybe you just didn't notice it.
 
yuppers, it's there. Stuck to upper half of drive....DUH!!! New impellor and plastic "GUIDE" pipe -now she runs coooool! But it seems that copper and plastic pipe have a lot of play between them? Possible source of cooling water leak...? Next time I'll fashion some type of collar to reduce play and help seal in cooling water.
 
There is a rubber seal that is in the top cover of the water pump cover that seals the copper pipe.


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