Alpha One waterpump replacement?

[Ag97]

Howdy everyone,<br /><br />I'm new to the boards and a fairly new boat owner. I just bought a 86 chaparral I/O (350 engine)last week and I'm having to replace the water pump and impeller. The guy that ran it before me ran with the l/u out of the water and melted the part of the housing around the shaft and ripped all the blades off the impeller. I've tried to get the lower gasket off the bottom housing but like I said part of it near the shaft was melted. I've got the replacement kit but I have a couple of questions. <br /><br />1. Part of the lower gasket seemed to melt to the lower housing of the water pump. I was able to use a knife and get most of it off but it is pretty rough looking around the shaft were most of the heat was. Do I and can I easily replace the lower part of the pump housing? <br /><br />2. Also when I pulled the lower unit off, the o-ring that was supposed to be up on the top part of the shaft was torn and was left up in the upper part of the unit. It looks like the there might have been another o-ring at the very top of the upper housing but I'm not sure. Is there just one o-ring up there are two. Maybe I was seeing a piece of the o-ring that was ripped in half. Is there an easy way to get all the parts of the old o-ring out of the shaft hole? What happens if there is part of the old o-ring up there that I miss? Also, the lubricant looks more like grease than lower unit fluid. Is it grease or should the shaft be lubricated by the lower unit fluid? <br /><br />3. Is there any was to find out where the rest of the blades from the impeller went to? Are they lodged somewhere or do they just eventually flush out? What do I need to do to get them out of the system?<br /><br />4. Is the small o-ring that they call the oil seal supposed to be round like a regular o-ring or is it supposed to be flat up on top and bottom to fit in the small cut out hole?<br /><br />Any other hints on what I need to be looking out for when I'm working on this thing? Any help would be greatly appreciated.

 

[tommays]

Re: Alpha One waterpump replacement?

http://www.boatfix.com/merc/mainmenu.pdf <br /><br />this a link to the different service manuals its better to have a paper one in your hand but this should get you started<br /><br />it sounds like you have a gen 1 which should be manual 6 but look around<br /><br /><br />tommays

 

[rodbolt]

Re: Alpha One waterpump replacement?

the small oring is called a quad ring and is supposed to be flat. if the lower base shows any sign of melt its a throw away item. the rubber pieces can be any where but if run without water they tend to fall behind the pickup screens in the lower case. on the upper. the drive shaft seal is in the upper housing. if its torn or the garter spring is missing it needs replacng. the driven gear seal for sealing oil in is inside the case. the oring at the top of the shaft assisted in keeping water out of the splines in event of a lower oil seal failure. later alpha's and all GenII drives eliminated the oring. make<br />sure the drive shaft seal is not damaged.most likly leaked some water in the uniut from the melted base. could be leaking from a failed lower seal in the upper. the driven gear seal seals oil in and tyhe lower seal in the upper for the drive shaft seals water out of the upper.<br />manual #6 is a wise choice. get it before going further.

 

[Ag97]

Re: Alpha One waterpump replacement?

Thanks for the info fellas. I looked through the service manual but didn't find too much that explained the replacement of the waterpump or impeller. I also couldn't find the schematic of how the lower and upper units would fit together. I'm guessing there isn't one since they are two different units that just happen to bolt together into a system. A couple of more questions also.<br /><br />1. What is the garter sping? Is it the little lip in the upper part of the stern drive that the shaft goes through?<br /><br />2. How hard is it to replace the lower plastic water pump housing? It looks like you just need to pry it up and replace it and the gasket but I may be missing something else in the process. <br /><br />3. Do I need to worry about fishing out the old pieces of the impeller blades or will they eventualy work there way out of the system?<br /><br />4. Was that grease on the splines of the drive shaft or do I have a fluid leak someplace and the drive lube just got hot enough to form a greasy substance instead of the liquid which I drained out?<br /><br />thanks again.

 

[Don S]

Re: Alpha One waterpump replacement?

Garter Spring???? No wonder you couldn't find any information on the water pump. You were looking in the Bravo service manual, and Bravo's don't have water pumps.<br />You need to look at the Alpha I service manual. Book #6<br />Section 3C gives you info on removal, inspection, and replacing the water pump.<br />At the end of Section 3B you will find information on putting the upper and lower sections back together.<br /><br /> Service Manual #6 Index

 

[Ag97]

Re: Alpha One waterpump replacement?

OK, one more question. I've gotten the lower section back together but am having a tough time getting the lower and upper sections to connect. I've tried to make sure the shift shaft is in the correct position but I think the splines on the drive shaft aren't aligning up at the top. I've tried to turn the shaft but can't get my hand up in between to turn it when I've got everything else lined up. I've tried turning the prop shaft but it doesn't turn the drive shaft. Did it come out of gear? If it did, how do I get it back into gear?

 

[Bondo]

Re: Alpha One waterpump replacement?

You have to shift it into Forward with the shift shaft,+ Hold Pressure on the Prop to Hold it in gear...........<br /><br />Make sure the water tube is lined up......

 

[Ag97]

Re: Alpha One waterpump replacement?

Well, thanks to you guys I seem to have everything back together and working. Now I'm just worried that I forgot something somewhere and left out a nut or gasket or maybe didn't tighten everything. I guess I'll be nervous until I run the boat a couple of times on the lake. I do have a couple of questions though.<br /><br />How much water should be coming out of the propeller when I have the muffs on? Most of the water seems to be coming out of the 2 ports up where the stern drive goes through the back wall of the boat. This is different from my old OMC. Should I have more than a trickle coming out of my Alpha 1? <br /><br />When I ran the engine to get it hot enough to drain the oil for an oil change the temp would never climb above 120 or so. Is this normal or do I have some of those impeller blade pieces stuck in my thermostat? I really don't want to pull the thermostat because of its location and it seems awfully hard to get to. <br /><br />Thanks for the help.

 

[aggiedave98]

Re: Alpha One waterpump replacement?

Fellow aggie here...<br /><br />Ag97, how hard was it to replace the water pump? I need to do that to my boat and haven't done it myself yet. I'm mechanically inclined (rebuild my old suburban's auto tranny) but don't know a lot about any one problem (like changing the water pump) until I do it. <br /><br />Any special things to watch out for? Does a bunch of fluid come out when you separate the upper and lower units?

 

[weatherz]

Re: Alpha One waterpump replacement?

Ag, tis normal for water to exit from the rear of the transom, very lttle comes out of the prop on muffs. The temp will stay low on muffs also because of no load on the engine and forced cold water from the muffs. Get out and run it, then you'll know if you have any more issues.

 

[rodbolt]

Re: Alpha One waterpump replacement?

the "garter spring" is the tiny circular spring that most shaft seals have to assist in keeping the seal lips on the shaft. usually if it rusts away or is damaged the seal will leak. volvo DP shafts in our area are very prone to it and once gone tend to leak.