Mercruiser Alpha One Gen 2 Impeller Repair

hi guys if you're watching this video you're probably interested in replacing your uh water pump impeller on your mer Cruiser Stern Drive um I'm going to do that on this uh alpha 1 Gen 2 um you can tell it's a gen two by the stainless steel housing the uh the Gen one and maybe even I think what they call the r has a plastic housing um different procedure for that it's a pretty simple operation uh there's a couple of things that you need to be aware of which we'll go over along the way uh one thing that I did is uh once you take it off of the uh the upper Drive housing which is a pretty simple thing uh there's two bolts on each side and then uh there's a bolt in the front and the back and uh you have to take off the uh anodes to be able to get to some of those but it's a pretty basic thing it's not hard to figure out may have to pry it loose a little bit depending on how uh old or how long it's been on there it may be corroded and sealed together but um as usual you don't want to use any uh heavy metal tools trying to break them apart or you'll bend them which can cause other uh other problems but once you get it off um take the time to put it somewhere where you can work on it uh don't try to set it up on uh concrete blocks and work on it in your driveway you'll just end up scratching it up and then you'll want to repaint that if you if you scratch it too much plus it's an awkward thing the way it's shaped it won't stand up by itself so uh go ahead and take the time to either try to mount it to your bench if you have some kind of a mount to do that I didn't so I made this uh wooden frame here uh only took about 30 minutes uh to do it I just had some scrap wood so I put it together um it sits down into it um so I know that it's not going to fall over on me it's stable and I can transport it back and forth uh to the boat uh in my car um so uh what I'm going to show you is I've already actually taken the pump off um and I'm just going to kind of go back through that procedure so that you can see what I did but before you really do anything go ahead and invest in a good mechanics manual like this one from seock I highly recommend this one um it's very detailed and uh accurate with its information um also make sure you have a marine grease this is 24c which is recommended uh actually by this manual I've also got some gasket sealer that I'm going to use um and then uh some touchup paint this is oilbased paint and then of course the uh replacement part for the uh the impeller and the water pump housing itself um is uh is all in here so I got the gaskets I've got the plate I've got the housing and all the pieces that come with that once you have all of that then you're uh you're ready to go ahead and uh take the old pump off so when you take this apart it's uh it's pretty basic um first thing you do is you take this off you know this is the water feed tube that goes up into your drive housing and on its way to the engine has two pieces to it this is nothing more than a guide tube so that when you put it back together the uh the main tube that fits into this uh mates inside uh this coupling and it has two O-rings in it which we are going to replace those but just set that aside for now clean it up and uh then the next thing that you're going to do is you're going to slide off this this rubber I believe it's called a a sling seal but it's effectively uh pushed down over the drive shaft onto the top of the housing and its purpose is not to keep water uh into from getting into the unit it's it's sort of the other way around because water is already inside the unit it's a water pump after all and so it just needs to slide down where it just barely touches against the housing to keep water from slinging out and up into your uh into your drive housing and other components but uh anyway you slide it up you take that off and then there's just four bolts like this that hold the whole thing down and uh once you have those off you can work off the uh the housing uh you may have to use uh something like this to pry it off you know again you want to be careful not damage anything when you take it off importantly notice which direction your impeller is rotating that's that's the impeller inside there it's a rubber impeller and you can actually twist it you know it turns supposed to turn but make sure you note the direction of which the uh the blades are rotating this is a uh this unit rotates clockwise this way so when it's on it's going to rotate the impeller clockwise which means if you're looking at it upside down uh it's actually counterclockwise so notice those are counterclockwise but in any case if you're not sure uh just make note of it and my recommendation with any of this stuff is uh take your phone out and take a picture of your parts if you're not sure and that way uh if you have to refer to them later you you have them you have them uh copied where you can see them so anyway set this aside and uh next thing is you know there's a plate here that you have to take off and uh actually have this one upside down it really should have gone this way um I've already disassembled this before I'm just walking you through what I did but uh this plate has a gasket on the bottom and a gasket on the top and uh this one you can see has a little bit of wear to it I can run my fingernail across it and feel the wear it's not significant but you know probably good to replace it once you take this off you'll want to clean this area really good around here mine was pretty clean but a lot of the paint had chipped off and uh the aluminum the metal was exposed in a couple of other places especially in the front here so I cleaned that up and again I used oilbased paint and uh and painted it just to make sure that all the metal surfaces were covered so that they wouldn't corrode and uh something that's really important to point out is and you're going to see this in other videos it's going to be mentioned anywhere you go anywhere near instructions for how to do this but this little hole here is the uh that's the gear lube transfer hole so that the gear lube that's coming from the upper Drive housing this is how it makes it down into your your gear assembly in the bottom through this little hole so there's a rubber uh a rubber o-ring there that you have to make sure that you take out and you replace it which it comes in your kit so you'll have one but don't forget to replace it but I even go a step further and I plug it up with something as I'm working on this because if you're going to scrape things like this you're going to get debris and stuff down in that hole and that's going to go right down into your into your gear assembly in the bottom so why do that so I would recommend plugging that up getting all of this nice and clean and uh and then once you do that uh then you're ready to put the new unit back on the other thing to make sure that you check out is run your fingernail up and down the shaft to make sure you don't feel any grooves um if you feel grooves that it means that something hasn't been wearing properly um this unit's only 2 years old and uh and so it was installed uh by the factory the last time the impeller was put together so there's no problem with this shaft but still check it out anyway just to make sure that there's not any problems with that you'll also want to take out the key on the drive shaft this is what holds the impeller in place your new kit should have a a new replacement for that let's look at what we have in the new kit most of them are pretty much the same this one has everything in it uh I've got a uh a new base plate I've got two gaskets the upper and lower got all the uh the rubber O-rings and there's a little tool in here a plastic tool um that's used to seat the uh the sling um gasket on the top of the shaft you cannot leave that on there it's just a tool that you press down and take off we'll see that in a second obviously our rubber impeller notice that the blades are not curved because it's new and straight and then um last last thing is we have the uh the housing itself stainless steel housing this is the new one um your old one may be fine so you can actually uh this is the old one that I have uh you can take it out I'm going to take the impeller out of it it'll hold that shape for a couple of days it'll eventually stretch itself out where it's almost straight but uh you can feel the inside of it run your fingernail and see if you feel any grooves and things like that in there if you don't you don't necessarily need to replace the housing it's perfectly fine um even in some cases you can inspect your rubber impeller and if it looks like it's in good shape and it's only been a year or two um you can probably even reuse it but while you're in here and you've already done all this work and you have all your parts you might as well just replace it with new stuff they're not that expensive and it's worth the investment so uh something that's uh important that that uh it's actually recommended in the mechanics manuals you'll see it on other videos too I thought it was a great idea and so I'm going to use this as well but I'm trying to line up all of the gaskets there's only one way that they line up so you're not going to get it wrong but they do have a little bit of wiggle room and that wiggle room is really important because you really don't want the uh the housing to be touching the shaft and you want to get everything lined up and so uh mer cruser sells these these little uh uh guide pins that that fit these screw holes and I don't know how much they cost but I didn't have them and I just went down to the hardware store and I got the exact uh thread size and these were bolts so I just took a hacksaw and I cut off the top of the bolts and so now I have these guide pins and what's important about these is if you look on your plate you'll notice that the holes are not all the same size I don't know if you can see that but uh two of the holes are smaller they're adjacent and two are bigger and uh so um I actually put these in the small holes so that when I put this down over it you know it has it has less room to play on it but anyway uh go ahead and um go ahead and create these they're useful especially if you're going to do this every couple of years this kind of stuff you're just building your uh invent T of suppli so that you can reuse it every time that you do this okay so now I'm ready to uh put it back together I got my my guides in there and uh I'm going to put the this first gasket on goes on First and like I said it only goes on one way so if it goes on the other way you'll know I'm not going to put any any uh sealant on the bottom side but I am going to put some on the top side and I'm just going to really put it around the outside here I'm not going to put very much just a little bit uh the uh the mechanics manual doesn't mention anything about putting gasket sealer on it but when I took the old one off I noticed that uh it had it on it so I'm just going to do the same thing there like that again it doesn't have to be very much and then I'm going to put the plate on next but before I do that I got a little bit of the sealer on the shaft and make sure I clean that off I got this on the right way is that the right way no it's not like I said you'll know immediately if it's not push that down like that okay and then now I'm ready to put the the next one on and I'm going to put a little bit of sealer on the top side of this as well so I'm just going to trace this around here see in other videos and they don't they don't use any sealer at all probably okay uh like I said when I took the old one off from the manufacturer the gaskets were stuck to the plate so figure it can't hurt okay done with that and now I take my top gasket and you want to it'll go on there one way I know I've said that a thousand times but you'll know because this one has a little rubber ring on the top that's going to mate with the bottom of the drive housing so I'm just going to press on that okay now next thing is we need the key so in the parts for your new kit you should have a new key and to make that key Stick I'm going to put a little bit of the Marine grease on it just a dab doesn't take much on the back side of it I'm going to rotate this shaft where it's facing me where I can see it just like that going to turn it around where you can see it okay now comes the interesting part there's two ways to put the impeller inside the housing this is the old one uh one way is you can twist it in yourself you have to make sure that you're putting it in in the right direction like we talked about so in either case you want to put some grease on the inside so that it twists in because it is a tight fit and it's not not an easy thing it doesn't just slide in um but I'm not going to do it that way I'm going to do it the way the uh the the mechanics manual says to do it and the way I've read and I heard from from some other mechanics that have done this is I'm going to put it on first I'm going to put the impeller on first and then I'm going to work the housing down over the impeller while twisting the shaft and to do that I'm going to use this so that I have a good tight grip on the shaft you can do it by hand but these things are kind of sharp and they'll cut into your they'll cut into your palm if you do it that way so I'm going to take my my uh my new impeller and I'm going to bring it down over the key you'll know it's only going to go one way bring it down over the key and then I'm going to take my new housing you have here and I'm going to put some grease on the inside smooth it out like this going to put a little on the top too what I'm also going to do is I'm I'm going to put just a little bit of grease on the leading edges of this now remember for my unit it turns this way it turns clockwise right so what I'm going to do is when I'm pressing the housing down over this I'm going to be forcing the impeller up into the housing so that way even if I forget which way these go they will set themselves and that's what they call it the propeller impeller is going to set itself in the right direction okay now I have my housing I'm going to set it down on top of the shaft this way okay and then just for some leverage I'm going to wrap this rag around the the top where I can get a good grip on on this like this and I'm hoping you can see this but I'm going to press down on the housing as I rotate this like that okay and now they're in there going the right direction and what I'm also going to do just so that you can see it but it's also to check it so now if you look they're going the right direction right so that's that's how you do that so now that I have it on there I'm ready to put the other screws in that hold it down so I'm going to leave the guide pins in while I do this and I'm going to put these guys in and something very important about it when you do this like I said before there's a little little bit of play in these holes where you shouldn't just tighten it down just because you have the screws in the right place and the reason is this housing should not touch the shaft if it's pushed over to one side the housing can rub against the shaft and that's going to cut a Groove in the shaft which obviously is no good so once you get it on here and you get it sort of snug like I'm about to do you'll want to kind of move it around so that you can visually look down and make sure that there's no way that shaft is going to touch the edges of that housing so I'm just going to Snug these down like this right and then I'm going to look at it and looks like it's pretty much perfect right there and then I'm going to Snug these down and when you do this just do opposite edges first don't do one too tight at a time got them all snug and then you can snug them down or they're tight they don't have to be real tight but you do want them snugged if you're not sure and you have a torque wrench check your manual and do the right thing and torp so the last thing that we have to do is we have to put this sling seal on it and this is pretty easy to do I'm just going to put a little bit of grease on the bottom of this seal and I'm going to press it on here with my fingers at first but then I'm going to use this tool that comes with it all this is is a tool and and the purpose of it is two things it makes sure that it pushes everything down nice and level and square so that it mates with the top of the housing perfectly flat but it's also the thickness of it is perfect so that when you do this all you have to do is push it straight down and when it stops it's at its perfect height and then the most important part is you take this off do not leave this on it's not really part of the seal it's just a tool if you don't have that tool some kits don't have the tool then the rule is that you need some sort of a flat type of a washer or a pipe or something that's just slightly bigger than the shaft and you slide it down and then as you're pulling up on the shaft you want to push down the seal to where it just barely touches the top of the housing and if you do that it'll be in its perfect spot but that's called seating the seal and you want to do it just like that you don't want to push it down with your fingers and you don't want it to be too high it should be just like that so now the last thing that we have to do to complete this is remember our uh our water tube that feeds into the the upper Drive housing has two O-rings in it those two O-rings are in my kit and you just take these out and you replace them with the new ones and as we mentioned before when you put this back together onto your upper Drive housing got the o-ring that's in here that came with the kit I'm not going to put it on right now don't forget the O-ring it's very very important and uh I actually have an extra gasket that came in this kit and I don't know what it's for so if somebody wants to post a comment to this video and tell me what you think it's for um I would appreciate it I didn't find anywhere where this went it it may uh it may go in the back or maybe it goes up here in the front but I can't really think of a place where where that needs to go so anyway uh that's how you replace a uh a water pump impeller on a alpha 1 Gen 2 Stern Drive hope this helped

Channel: Jonathan McClure

Views: 264,879

Keywords: Alpha One, Impeller, Mercruiser, Boat

Id: N4qK605w_0Q

Length: 25min 46sec (1546 seconds)

Published: Wed Nov 04 2015