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View Full Version : How to: Impeller Change ( very pic heavy)


baitsauce
12-03-2008, 09:28 PM
Since I'm sure a lot of boats have been put away until spring I think this may be a very timely post, as now is the time to do a little maintenance.

I bought my kicker new and have never changed the impeller. So I figured it was probably about time. I started researching on how it’s done. One of the places I started was our forum (ifish). I looked though it pretty hard and was surprised when I couldn’t find much here on how to change an impeller. So after more research I figured it out and in an effort to make this forum better I decided to make this post. Maybe it will be of some help to someone.

The first thing I did was to note the make (of course), the model, and even the serial number of my motor then go to my local dealer. $20.50 later I walked out with a new impeller.

A disclaimer: Although this is a simple and straight-forward task, this is how I changed the impeller on my motor. On different makes and models I can’t imagine it would be much different. Like in poker you have to play the cards you’re dealt, so you may have to make some adjustments particular to your motor. This is what I did on mine, a 2002 Mercury 9.9hp Bigfoot with an extra long shaft.

Obviously, the motor was removed from my boat and in the garage with the Serius radio on the AC/DC channel. :D

http://www.ifish.net/gallery/data/505/00124.jpg



Then the bottom cowling was removed to make it easier to get to the shift linkage coupling.

http://www.ifish.net/gallery/data/505/00221.jpg





http://www.ifish.net/gallery/data/505/00320.jpg


Loosen the jamb nut. (circled) Then separate the two ends. After separation, remove the jamb nut.

http://www.ifish.net/gallery/data/505/0046.jpg


Then remove the bolts connecting the lower unit. Circled here in green. Because this particular motor is an extra long shaft, it has a “spacer” between the bolts circled in red and circled in green. I first removed the bolts circled here in red, but it turned out it wasn't necessary.

http://www.ifish.net/gallery/data/505/0057.jpg



When you remove the bolts be careful and slide the lower unit STRAIGHT off. If it doesn’t come off then a little (and I emphasize a little) persuasion with a rubber mallet may be needed.

Here is the lower unit (with the spacer still attached):

http://www.ifish.net/gallery/data/505/0064.jpg



Here is the lower unit with the spacer removed:

http://www.ifish.net/gallery/data/505/0074.jpg



Take the lower unit someplace comfortable and easy to work on. In this case the swim deck on the back of my boat served quite well. The impeller housing has the driveshaft going through the center. While you’ve got it apart it is a really good time to inspect everything. I run my boat quite a bit in the salt and was very happy with what I found.

http://www.ifish.net/gallery/data/505/0085.jpg



Now remove the bolts that fasten the impeller housing onto the lower unit and pull it all the way up and over the driveshaft.

http://www.ifish.net/gallery/data/505/0095.jpg



Take special note of the woodruff key and slot (circled). And set the woodruff key to the side and do not loose it!!

http://www.ifish.net/gallery/data/505/0106.jpg



Here is a close up of the woodruff key and slot:

http://www.ifish.net/gallery/data/505/0119.jpg



The (old) impeller is the star shaped rubber part inside the housing. The new impeller is in the bag. Although not pictured, on the old impeller had the same part number embossed on it as the new one. In short, is the same part number as the new one. May want to make sure of that before you open the bag as once opened the part(s) can’t usually be returned.

http://www.ifish.net/gallery/data/505/0125.jpg



Be sure to wipe everything down. I used a little soap and water. Then put the woodruff key in. I dabbed a little marine grease to help hold the woodruff key in place.

http://www.ifish.net/gallery/data/505/0133.jpg



Slide the new impeller, the nylon spacer, then housing over the driveshaft; indexing the slot on the new impeller over the woodruff key.

I would strongly recommend coating the inside of the housing with a lubricant. I used a little marine grease. But I would think Vaseline or even liquid dish soap would work. Just make sure whatever you use will not dissolve rubber, as that is usually the material the impeller and o-ring are made of.

If you look closely I “dry fitted” the new impellor in the housing. The blue is the marine grease I noted above. The trick to putting the new impeller into the housing is to turn the driveshaft CLOCKWISE as you are gently pushing the housing over it.

http://www.ifish.net/gallery/data/505/0143.jpg



Once the housing is on, thread the bolts and tighten. Do not over tighten. Remember, the bolts are being threaded into aluminum. Also, since the bolts are stainless, anti-seize is strongly recommended because of the corrosion potential associated with dissimilar metals.

http://www.ifish.net/gallery/data/505/0165.jpg



I applied a little marine grease onto the end of the water tube that goes into the impeller outlet. Then simply reassemble your lower unit of your motor in the reverse order it was removed.

I had a little trouble lining up the impeller housing outlet to the water tube. But once it lined up the lower unit more or less just fell together. Then as stated before a little anti-seize was used on the bolts connecting the lower unit.

A note of caution: Because of the way the impeller works, it is imperative that once installed, the driveshaft NOT be turned backward as I believe it will probably ruin the new impeller.

This was very easy to do. If you can change spark plugs then you should have no problem doing this yourself. In fact this would have taken me well under an hour if it weren’t for all of the pictures I took for this post and having to return to the fridge to replace an empty beer. :D

Also, it is interesting to note the there is nothing wrong with the old impeller. In fact I see no reason I can't reuse it. I was a little surprised because as I alluded before the old impeller was installed by the factory six years ago and I log from my educated guess between 300 and 500 hours a year.

Good luck and have fun!! :cheers:

Hawaiian Time
12-03-2008, 10:35 PM
Thanks for the pictured step by step tutorial..good job..HT

Elk Mania
12-08-2008, 09:07 PM
:meme: good job

jordanb38
12-08-2008, 09:33 PM
For all concerned pkease note that even in different years, theres a big difference. Most lower units come apart in a very similar manner, but they often have much different assemblies. This is an AWESOME example, but you can save yourself some serious time and money buying a service manual to identify part orientation, installation/tear down order and torque specs.

bluehewes
12-09-2008, 01:02 AM
Nice post!

I've done a few and for the most part everyone I've done has been a little different but pretty much the same. You can also by a kit that replaces the housing and all. I think for my 200hp yami it's about 65 bucks.

kscheffler
12-30-2008, 10:03 AM
I was reading my operations manual for my Mercury and they had conflicting instructions regarding wether or not you pulled the shift into gear or not. Does it make a difference if you have the shift in neutral or not?

Deanrt
01-10-2009, 03:31 PM
Great thread Devil Dog:D. I really like the part about AC/DC and the trips to the fridge:meme: