Help changing impeller

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Tally Ho

Tally Ho

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Jan 7, 2011
5,916
Oday 322 East Chicago, IN
So I went out to the boat this morning (on the hard) to change the impeller. Watched some videos, thought I had it figured out. On my Yanmar 2GM20, you have to take me water pump off of the engine mount to get to the back side...all went smooth, got the cover off, took a photo so I knew how to reinstall the impeller vanes....

But I cannot get the impeller off of the shaft and out of the housing. Is there a trick for this? I see the key way, but I assume the impeller just slips off of the shaft...

But no go.

I brought the housing assembly home to work on it....but have just managed to break all of the rubber vanes off of the impeller...

Any help or thoughts?



image-941260041.jpg
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Most diesel engine pumps have seals inside the pump, two seals: water and oil, keeps them from leaking out or mixing. You can most likely find your pump at www.marinedieseldirect.com. The shafts come and go.:)
 
Charles Erwin

Charles Erwin

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Jan 30, 2012
1,154
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
You just need to pry it out.

Needle nose pliers - one jaw at the shaft end the other one outside on the impeller. Wiggle twist pull. Use small screw driver or ice pick. Jam the blade in the impeller center, pry against the pump body as fulcrum.

Have faith be aggressive and don't wimp out.

I know because I did 4 this week. One day I will make a miniature crowbar to reach between the impeller vanes, jamb under the impeller center and pry it up and loose.

Charles
 
T

Tejas

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Dec 15, 2010
164
Beneteau First 36.7 Lake Travis
I use an impeller puller as suggested by justsomeguy. The puller is on the boat, and I don't recall the brand. Defender.com has pullers.
 
DougM

DougM

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Jul 24, 2005
2,242
Beneteau 323 Manistee, MI
I have a 2GM20F and your impeller/pump is different from mine. Yes, The easy thing is to disconnect the pump. The difference in mine is the the impeller has a crosswise dowel the sits in a notch in the pump shaft. Also, my pump cover has an O ring seal, and no gasket. I can grab the cross shaft with a long needlenose and pull the impeller right out. Whole job takes 15 minutes.

I had always heard that there were two different pump versions on the 2GM20, one on the Euro version and one on the Japanese version. I guess your photo proves it.
 
Dave602

Dave602

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Jan 22, 2008
321
Hunter 29.5 Gloucester, VA
I have the same pump on my 2GM20F. If one is difficult I have used channel lock pliers and have been able to get it out.
 
Warren Milberg

Warren Milberg

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Dec 1, 1999
2,391
Hunter 28.5 Chesapeake Bay
Don't panic, this is a common problem with raw water pumps. I have the same engine and have had this problem a number of times. I usually take the pump home and put it in a vise to hold it securely. I put a pair of pliers on each side of the impeller and grab a vane and pull very hard. It helps to squirt a bit of liquid soap on the shaft first to loosen things up. If all else fails, beg, borrow or buy an impeller puller. FYI, here is how Don Casey deals with the issue:

http://www.boatus.com/boattech/casey/replacing-impeller.asp

When you get the old impeller out and the new one in (a whole other story and technique) don't worry which way the vanes face -- it just doesn't matter.
 
Charles Erwin

Charles Erwin

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Jan 30, 2012
1,154
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Should I think $100 for an impeller puller is a bit much? Elegant.

Screw driver/ice pick technique. Not so elegant. Thanx to Milberg.

Charles
 

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Jerry Clark H356 SV Persi

Jerry Clark H356 SV Persi

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Mar 3, 2003
710
Hunter 356 Grand Rivers
The puller the describe is simple like a miniature crowbar that you use to wedge against the side of the rubber of the impeller while using the pump face as the lever point. Put some liquid soap on it inside the shaft and use a small screwdriver as a crowbar. Also get hold with needle nose pliers of a vane, possibly use two pliers and pull out while twisting it on the shaft. Mine doesn't look exactly like your (3GMF30), as the shaft has a straight bar that goes across.

Once you complete this exercise, I recommend you look up Speed Seal Life on the Internet and get one of their kits. It also comes with a removal tool that works. They recommend white lithium grease be applied when installing and it should assist you in future removals and replacement. It will simplify future changes. You should check your impeller at least annually and if the slightest bit worn where the blades attach to the center, replace it.
 
onecoolair

onecoolair

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Jun 25, 2012
942
hunter 356 Kemah,the Republic of Texas
Charles Erwin said:
You just need to pry it out.

Needle nose pliers - one jaw at the shaft end the other one outside on the impeller. Wiggle twist pull. Use small screw driver or ice pick. Jam the blade in the impeller center, pry against the pump body as fulcrum.

Have faith be aggressive and don't wimp out.

I know because I did 4 this week. One day I will make a miniature crowbar to reach between the impeller vanes, jamb under the impeller center and pry it up and loose.

Charles
Click to expand
"DITTO" Same here .... If the impeller is already toasted then just grab on to one of the vanes with needle nosed pliers and wiggle it out. Look closely to see if there is a "C" clip on the end of shaft ...Very rare to have a "C" clip here holding the impeller on the shaft, but you never know?
Now If someone manufactured a mini puller for this that would be cool!......PM me for were to wire the royalty payments to my offshore account....:D
 
Tally Ho

Tally Ho

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Jan 7, 2011
5,916
Oday 322 East Chicago, IN
This is why I really like this Forum! Great advice and lots of help!

I finally got the impeller out, using most of the advice provided (except for the puller...don't have one)...

I had to pull all of the rubber vanes off, and pry most of the rubber off the hub, so I could get some channel locks on the hub....lots of WD40, lots of pulling and wiggling...and probably not enough patience ;-).

The only thing I am concerned about is that when trying to pry the thing out with a screw driver, I affected the edge of the housing a bit. I hope the cover seals tight.

This is the first time I have changed the impeller in 2 seasons of use. Not sure when the PO last changed it. I guess I better take it out annually from now on.

I can confirm that, at least on my version of the pump, and with the cover off, the direction of the vanes at installation is not important...as soon as I turned the pulley, the vanes laid down in the right direction.

Thanks for allow the great help. I may have to invest in a puller...will check them out.
 
Tally Ho

Tally Ho

.
Jan 7, 2011
5,916
Oday 322 East Chicago, IN
Charles Erwin said:
You just need to pry it out.

Needle nose pliers - one jaw at the shaft end the other one outside on the impeller. Wiggle twist pull. Use small screw driver or ice pick. Jam the blade in the impeller center, pry against the pump body as fulcrum.

Have faith be aggressive and don't wimp out.

I know because I did 4 this week. One day I will make a miniature crowbar to reach between the impeller vanes, jamb under the impeller center and pry it up and loose.

Charles
Click to expand
Thanks Charles. Took more aggression than I thought. I was worried about damaging the housing when prying on the impeller. I did ding it up a little right on the edge...I hope it seals..
 
Tally Ho

Tally Ho

.
Jan 7, 2011
5,916
Oday 322 East Chicago, IN
DougM said:
I have a 2GM20F and your impeller/pump is different from mine. Yes, The easy thing is to disconnect the pump. The difference in mine is the the impeller has a crosswise dowel the sits in a notch in the pump shaft. Also, my pump cover has an O ring seal, and no gasket. I can grab the cross shaft with a long needlenose and pull the impeller right out. Whole job takes 15 minutes.

I had always heard that there were two different pump versions on the 2GM20, one on the Euro version and one on the Japanese version. I guess your photo proves it.
Click to expand
Hi Doug....funny thing is that the PO had several spares on the boat. The first one I pulled out was as you described...with the center dowel (and an oring in the kit). I could not figure out how that was going to go back in..opened the 2nd spare, and viola...it was different...with the key way....

I finally got it...I think your design is a whole lot easier to pull out. But maybe mine was neglected..I will pull it out more frequently now that I know how it comes apart.

Thanks for the help.
 
Tally Ho

Tally Ho

.
Jan 7, 2011
5,916
Oday 322 East Chicago, IN
Dave602 said:
I have the same pump on my 2GM20F. If one is difficult I have used channel lock pliers and have been able to get it out.
Click to expand
Thanks Dave...that is what finally got it out. Stripped most of the rubber off the hub, got,some channel locks on it and wiggled and pulled.


Thanks for the help.
 
Charles Erwin

Charles Erwin

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Jan 30, 2012
1,154
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
OK
Assume you mean the inside edge of the pump body - the corner of the surface where the vanes meet the body.

If so - then use a sharp knife to gently scrape (not cut) the burr off the edge. Then smooth with 220 paper. During the process stuff the impeller cavity with tissue paper to catch any debris. Take your time, gentle, and smooth. All you are trying to do is make sure there are no burrs to catch the new impeller. Small, smooth imperfections will make no difference.

Clean the interior of the cavity -- hot water soap and a tooth brush plenty of rinse. I believe in reassemble with surgical clean parts.

Charles
 
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