Water Pump Change

'04 Merc 115 Four Stroke EFI

Anyone have an idea how difficult it is to change the water pump?

I did one on a 25HP Evinrude, years ago and it didn't seem that hard.

Watched some youtube videos and my biggest worry is the shift linkage I guess.

Any thoughts?

Were you running it with earmuffs looks like it could have been running dry and backwards 

Yeah that definitely looks like the impeller was installed the wrong way, the shaft turns clockwise and if you install it with the impellers bent the wrong way that would be the end of that. Don't feel bad that is a common mistake. When you get the new one make sure you put lithium grease on the impeller the shaft and the shaft key to help hold the key in place.

That's kind of what it looks like impellor in backwards, it appears that it was spinning in the wrong direction.

Chalk up another fail for me.

Watched the YT vid 20 times, followed all instructions. Watched it while assembling.

Was barely pissing.

I pulled the lower unit again and the new impeller looks ten times worse than the old one. Housing was clean, no grooves, applied light coat of marine grease and after ten minutes (maybe) of running this is what I ended up with. (see pic) 

Great thinking to check linkage before putting it in the water.

I have an 0/3 Merc,the pump looks exactly the same. The thing you have to watch out for is not to turn the female shifting linkage that is located on the side of the water pump. It takes a little to get that shifting linkage together when you are putting a lower unit on but if you take your time and should work fine.

No You can shift it when running with muffs out of the water.  Lower unit oil protects gears.  Linkages are sometimes out of water when shifting in normal situations (high tilt)

Got the new pump installed after work.  Forgot I promised my wife I’d take her out to a new restaurant she wants to try tonight so not sure if I’ll get the lower unit remounted to the motor yet tonight.

As mentioned, after I get it all back together, I want to start it up in the driveway with the muffs on. Does it hurt an outboard to shift it in forward and reverse when it’s out of the water?  I’d like to verify that the linkage went back together correctly before hitting the water.

I can't find the video where I saw that your 5th bolt/nut may be under the adjustable fin but look under there if it's not in front of the fin.

I don't have the best shop either and it's got to be 100 degrees in my garage in the middle of the day.  I have a vice on a workbench in my basement so that's where I'm working on the pump.  When I get frustrated, I just walk away, pick up a guitar, drink a beer or just plain calm down on the deck for a while.  I don't work well angry either.:)  I hope to at least get the pump back together tonight.  Hopefully I can get the lower unit on the motor too but we'll see.  For me, testing it in the driveway with the muffs is the part I'm worried about the most.  If it doesn't work, I may go all Clark W. Griswold.

I think I missed a bolt as you said in the PM - Just a heads up for anyone that stumbles across this thread.

I looked around, but don't have the best "shop" to be doing this in, i.e. the 110º garage, lighting not the best, etc. and got frustrated for the evening and called it quits for the evening.

I'll have to take a closer look later on when the daughter takes a nap.

I should be able to get everything in order by December or so, Then it's on to carpet.

I would have sold the boat and cut my losses, but I got it from my dad when he passed and it's basically the boat I want for walleye/musky and is set up how I want it, for the most part anyways.

Appreciate all the help.

I'm not experienced enough to know if a housing is warped.  But if you can verify that it isn't warped or scored on the inside, I'd reuse it.  As we've discussed here and on the messenger, I have the 2-stroke and you have the 4 so I'm not sure if the lower units are identical.  For my motor, there are three options.  You can either just replace the impeller or there are two kit options.  First kit includes the impeller, the lower plate, the shaft key and gaskets.  The second kit is the entire pump assembly including the upper housing.  The impeller alone is about $15.  Kit 1 is around $35 and Kit 2 is $116.  I would have gone the cheapest route had there been no damage to the metal parts but that's not the case so I'm going with the whole replacement.  I may have gotten away with reusing the old housing but I would be going through impellers a lot quicker.  Hope this helps.  Did you get your lower unit to drop?

If the housing isn't torn up or scored, I should be good with a new impeller and gaskets, correct? 

Or should I go whole shebang?

Edit: I saw PLM's post, any way to check to see if it's warped?

I like to replace the housing along with the impeller. 

I used to have a Mercury XR6 that was overheating. I replaced the impeller with no improvement, so I began to suspect the thermostats.   I pulled them out, and put them on a pot of water with a thermometer on the stove, and they popped open right when they should. 

Long story short,  after having that thing apart a few times, I eventually figured out that the housing was warped.  

From that point forward, I have always replaced the whole shooting match.  

It's not brass but I'm replacing the entire pump.  Base plate, housing, impeller and gaskets will all be new.  Before the sand tore up the impeller, the base plate and housing both got scored.  I bought the pump kit at Skipper's Choice in Green Bay.  $116 with tax.  That's for a 2004 Merc 90 HP ELPTO.