Impellers - Lessons Learned

[egaito]

So, with the evening coming to a close, I've finally managed to replace the impellers on Sanctuary.

I'm embarrased to say it took the better part of two days, but thought I would share the lessons learned.

First, the impeller puller sold for this purpose leaves something to be desired. Granted, the job would have been much harder without it (thank you Pascal), but the "prongs" on this thing only go about half way down the impeller, and are designed to bite into the rubber to pull the impeller out. Invariably, one side lets go, and it took several passes on each impeller to get it out. On the 2nd one, I learned to put pressure on it with the impeller puller, then use the old technique of screw drivers to "inch" it out. It went much faster this way.

Putting them back in was a bit of a challenge, but not terribly bad. One thing I learned here is that I don't like KY as a lubricant (for this job anyway). Besides not offering the "sliperiness" (sp?), I prefer to have some type of grease on the shaft as I'm convinced the lack of this was part of the difficulty pulling this set of impellers out. So for the 2nd impeller, I used a light grease, which seemed more slipery going in as well as making me feel better about the impeller perhaps not siezing to the shaft as easily next time.

Beyond the lubrication, getting the new impellers in proved quite a challenge. Several wire ties around the blades to "pre-orient" them worked well. Unfortunately, there's just not much room to work behind these engines, and the room that is available is tangled with exhaust cross-over hoses. Finding the leverage to tap the impeller in on the first engine was tough as the starboard engine room has the air conditioner rack on the aft wall, and ultimately took two people, one to hold the screw driver (we were using the handle to drive it) and the other to tap it. On the 2nd engine, I was able to accomplish it myself, but not without the aid of the specially designed, and patent pending, "Articulating Impeller Driver" (see attached picture). With a little grease, and this amazing tool, I was able to seat the 2nd impeller on my own by going in at various angles around the intruding hoses. Since you all are our friends, I'll share the plans...duct tape a dowel cut to the appropriate length for your boat, to the end of a bung, and bang away.

Of course, another lesson learned is to vacuum out the bilge before you start as I spent a good amount of time wiping nasty water and oil off tools, screws, and myself during the course of the job. But you already knew that, as did I ;-)

Oh yea, and when "bump" the starter to move the impeller a bit....make sure your finger is on the "shutdown" button! These engines start WAY too easily.

After all of this, the impellers that I pulled weren't all that bad, but at least we have the piece of mind of knowing when they were replaced, and one of them came out in good enough shape to become a spare.

So that's the story, suggestions and questions welcome!

 

[Passages]

How long has it been since the impellers were last pulled? I pull mine every fall de-commissioning, inspect it and the wear plate. If all is good, will reuse it for 1 more year. Comes out with minimal swearing.

Prior to reassembly, I'll coat the shaft with bearing grease or anti-seize. Even though I can drive the impeller back in with well place knee or foot, I like the custom impeller driver you came up with.

 

[egaito]

How long has it been since the impellers were last pulled? I pull mine every fall de-commissioning, inspect it and the wear plate. If all is good, will reuse it for 1 more year. Comes out with minimal swearing.

Prior to reassembly, I'll coat the shaft with bearing grease or anti-seize. Even though I can drive the impeller back in with well place knee or foot, I like the custom impeller driver you came up with.

It's hard to say when they were last inspected. The previouse owner passed away in '04, so it's probably a safe bet to say that they haven't been out since then. Based on the condition of the impellers and shafts, I would say that no anti-sieze, grease or otherwise was used. These things were tight, and came out 1/16th at a time until the last 1/4 of their length. I've never encountered a set as tough, though there was no cracking at the base of the vanes, and the tips were in good shape. The port engine was a little worse for the wear as the last "mechanic" used what appeared to be corregteed cardboard to make gaskets out of, with some type of sealer that calcified inside of the pump chamber. A mess to get rid of.

I agree on the grease, and have always used it on my boat, but Ang was a bit wary as she had read that it would damage the impeller somewhere, so I tried the KY....should have stuck with what I know, and won't try it again. I've always pulled my impellers with a pair of needle-nosed pliers, so I must be doing something right.

 

[Nonchalant1]

DD service manager here (15 years working on DDs in boats) says to use vaseline. I also discovered that an automotive piston ring compressor works nocely to compress the vanes so you can knock it in with a wood hammer handle. Don't forget to grease the splined shaft and inside the impeller core too. Next time, you may want to check for a rough splined shaft. The shaft is as old as the boat and may be pitted or rough. It can be removed and shined up with a dremel (but don't grind anymetal off it, just smooth out the roughness).

Doug

 

[egaito]

DD service manager here (15 years working on DDs in boats) says to use vaseline. I also discovered that an automotive piston ring compressor works nocely to compress the vanes so you can knock it in with a wood hammer handle. Don't forget to grease the splined shaft and inside the impeller core too. Next time, you may want to check for a rough splined shaft. The shaft is as old as the boat and may be pitted or rough. It can be removed and shined up with a dremel (but don't grind anymetal off it, just smooth out the roughness).

Doug

I've heard the ring compressor trick, but not that that the shaft would come out. How does that work, is it threaded? If so, I'd like to canabalize one of the old impellers to make a removal tool.....

 

[Genesis]

The shaft in the pump does NOT come out - at least not easily! You have to take the pump apart!

Here's my take on it:

1. The Jabsco impeller puller is the VASTLY superior tool for this job. The two screwdriver deal is WAY inferior.

2. Its tight in there to get to it, but not impossible.

3. For reinsertion I use KY on the vanes and trailer wheel-bearing grease on the splines The big problem is the vanes, which are very stiff and near the cam will not want to go in and/or will hang up. That's where the zip ties come in.

A well-placed foot works well in my experience to solve THAT problem.....

 

[Captned]

I hire a big boy here at the marina and oversee the operation. Combination of boy, Jabsco puller, grease and zip ties get the job done. Best $50 bucks spent yet. ($25 per side)

FWIW- One of them was giving us grief last time, the Jabsco arm kept sliding off of the impeller. I went and got my trusty vise grip with chain links, clamped it around the puller arms and locked them down TIGHT! No more slipping after that...

I don't really understand why one would stick like that. Every year one or the other seem to stick. I change them every spring and grease the heck out of the splines...

Captned

 

[Nonchalant1]

I've heard the ring compressor trick, but not that that the shaft would come out. How does that work, is it threaded? If so, I'd like to canabalize one of the old impellers to make a removal tool.....

YOu have to take the pump off the engine and take it apart. It's not that hard to take off if you can reach it.

Doug

 

[Courageous]

I have used swimming pool waterproof grease avalable at pool supply stores for years on Jabsco pump impellers. Its green and sometimes some is left on the impeller from the year before.

Courageous

 

[Genesis]

I don't really understand why one would stick like that. Every year one or the other seem to stick. I change them every spring and grease the heck out of the splines...

Captned

They're hanging up on the slots in the cam; the splines aren't the problem. There's no real fix other than bump the engine a bit if it happens (remove the tool first!) and then try to pull it again.

 

[CARL GUZMAN]

Hay poohbah you still awake

 

[MikeP]

I used to use hose clamps to help installation but I have found that using wire ties or hose clamps for impellor installation on our 8V71Tis are unnecessary. I use plenty of vaseline on the impellor, shaft and the walls of the pump. Then I place the impellor on the shaft BUT WITH the key just barely out of alignment (so the impellor will turn almost a full turn without the key aligning) and simply press and turn the impellor in the proper direction. The pressure (pushing) and lubrication allows the vanes to fold themselves as the impellor turns. When the spline aligns, the impellor will slip in an inch or thereabouts. It goes in quite easily most of the way by hand, a final shove with my foot seats it. I've put the last two sets in this way.

Plenty of lubrication makes this almost painless!

I replace the impellors every season, using the previous season's as spares and tossing the (new-looking) ones from the season before that. Doing it every season is probably overkill but 160 bucks for a couple of impellors every year and 30 minutes work isn't much of a time/money issue in the 53MY boat maintainance pantheon!

 

[Bob Bradley]

Regular dish soap works well as a lubricant also.

 

[Boatsb]

I bought my boat from the guy who never maintained it. One pump needed to removed so I could take off the impeller with a sawzall. Shaft was the old bronze and the bearings were probably original on 1966 engine. I sent the whole tihing to depco for a rebuild and had it back in 2 days. For the other there was a newer SS shaft. I cleaned it up well and lubed with anti sieze ( per Depco) and lubed the vanes with Dawn dish soap. Not only does it make for a nice easy slide into the housing but it also helps prime the pump and is ease yo see that the pump is working after the engine starts. Bubbles and all.

I will remove and inspect the impellers each year for the price of a gasket set and that should prevent the freeze on the shaft problem. Also I will replace the zincs at the same time ( the last guy didnt seem to do that either.)

 

[John Dickson]

On the Jabsco units, what do you guys recommend to use on the paper gasket to seal for imperfections?

 

[Genesis]

A VERY SMALL amount of RTV if you need it at all.

The paper gaskets do not normally need sealer.

 

[John Dickson]

Thanks Genesis

jd

 

[Nick]

A while ago someone on the forum recommended the puller made by Ruko. I bought it after the Jabsco puller crapped out on me and the threads stripped.


The Ruko is a far better tool than either the large or small Jabsco puller. It is not cheap, but good tools are worth it. Makes the job a piece of cake.

http://www.rukoproducts.com/Pages/impller.html

Thanks to whoever suggested this to me!

 

[krush]

I just use a bunch of wheel bearing grease and then squish the vanes enough to get the key lined up then just bump the engine over while pushing in on the impeller.

 

[Finalee]

I drilled 2 holes in the rubber splines as close to center as possible, and then looped a coat hanger thru and twisted the ends to prevent the loops from slipping. Then used 2 1x1s and levered the impeller out. Wd40 for lube. The zip tie trick worked good for assembly along with a rubber mallet to tap it in. Must admit that I tried several other methods first to no avail.