2 Yanmar Raw Water Pump questions

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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
I was replacing the raw water hose that runs from the strainer to the pump and opened up the enclosure to inspect the impeller. I removed the gasket and replaced it with one I cut out from a sheet of cork gasket. When I started the engine I noticed that the flywheel was wobbling violently. In addition the water was not being pulled through the system. Yet everything was open.

Questions:
1) Do I need to prime the raw water pump?
2) Before I rip apart the pump to see if there is something wrong, I would prefer to get your thoughts about the violent wobbling.

Thanks -Jon
 
kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
Hello, Jon..
The gasket for the pump cover must not be any thicker than a sheet of paper. It is "function critical" that the cover just barely touch the side of the impeller when the impeller is seated against the back side of the case..
The pulley that is wobbling is very easy to bend when working on the pump. You can also easily (carefully) bend it back straight, or replace it .. part # 124070-42400; about $20. It is mounted with only that one nut, so before trying to straighten, make sure the pulley is lined up on the shaft flats and the washer is too. Tighten the nut and look at which way the pulley is wobbling. gently by hand, bend it back to straight. Takes about four iterations to get it back (some experience base here).
 
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Capt jgw

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Feb 8, 2014
1,300
Columbia 36 Muskegon
The first time I took the cover off the pump on my then new to me boat, I found it had no gasket and was sealed with Form a Gasket. It had been working just fine, so I guess in a pinch that will get you by. Those thin paper gaskets are darned near impossible to reuse. The newer pumps have o rings. When you buy replacement impellers you can get them with or without gaskets, make sure you get the gaskets.
 
woodster

woodster

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Sep 15, 2009
6,243
S2 9.2a Fairhope Al
the yanmar guy down in pcola told me to use blue locktite on the nut and to also use an impact to install the nut as it would give me longer service life before coming loose ...also the binding that claude suggested is a good fix for the wobbling pulley unless it is really old and rusted out ...i keep a spare pulley on board just incase
 
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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
Your were right Claude, it bends very easily and is probably better replaced. So, I just ordered a new impeller, paper thin gasket and V-Pulley.

Thanks Capt jgw.... I'll try and straighten it out and keep it as a spare as you suggest.

As for my other question, does the pump need priming or will it pull in the water?

Thanks... Jon
 
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woodster

woodster

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Sep 15, 2009
6,243
S2 9.2a Fairhope Al
will not hurt to prime it but i have found that the min the pump stats turning that the water fill up very quickly in the system
 
kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
Put a little SuperLube on the inside of the case and it will prime itself. Best to not let it fill the strainer so it is good practice to open the seacock for a few seconds, and fill the strainer and hoses.. then hook to pump and crank her up. It only takes about 30 seconds to destroy an impeller if there is no grease or water in the pump.
http://www.amazon.com/Super-Lube-21030-Synthetic-Grease/dp/B000XBH9HI
Keep a tube of that stuff on board for general lube.. Really an excellent lube for head piston rings and valve O-rings and stuff.. Suitable for winches too.
 
splax

splax

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Nov 12, 2012
694
Hunter 34 Portsmouth
The wobbling may have been due, in part, to the cavitation and space created by the thicker gasket.
 
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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
Thanks Woodster & Splax.. The wobbling was very clearly caused by a bend in the pulley where sits on the shaft. But I never would have guessed it. I think I can hammer it flat.

Superlube ordered... but I was thinking the KY might have worked...

-Jon
 
kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
KY is for deck wenches... Superlube for deck winches!
Superlube is available at WalMart and Harbor Freight and sometimes in Lowes/HomeDepot/Ace
 
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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
Ahhhhh Thank you for the clarification Claude! Yikes we're both going to get banned from here! Ordered it from Amazon... for the winches of course!
 
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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
Pulley Straightened

The arrows in the picture shows where the pulley was actually dis-formed.
I was actually able to straighten out the pulley by using a hammer and a flat surface.

-Jon
 

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kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
Perfect, Jon ! Note: not to side load the pulley when tightening the belt.. Little bugger can be easily deformed.
 
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Dan_Y

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Oct 13, 2008
517
Hunter 36 Hampton
+1 on thin gasket. My raw water pump on the 2gm20f quit drawing at idle due to the wear grooves on the inside of the cover. I first replaced the impeller and once the lube wore off, it quit drawing. A new cover and gasket fixed it. I always flush the engine with 4 gal of fresh water when putting her up and it usually takes about 70 sec at idle to empty the bucket. One day it just stopped drawing at idle.
 
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Capt jgw

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Feb 8, 2014
1,300
Columbia 36 Muskegon
Speed Seal makes a kit for most of these pumps, it's a new cover with thumb screws and an o-ring seal. No tools needed to remove and the o-ring should last a long time. I've never used once but they look pretty good.
 
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PGIJon

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Mar 3, 2012
856
Hunter 34 Punta Gorda
Claude.. Please forgive my ignorance but could you please explain how I avoid side load. Do I just keep the belt loose?

Dan.. thank you for the insight. I'll do that.

Capt.. I already have mine coming from the Yanmar distributor here but I'll look into the Speed Seal. I would definitely prefer an o-ring seal.

Thanks all! -Jon
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
It might be a good idea to at least fill the strainer with water/
 
woodster

woodster

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Sep 15, 2009
6,243
S2 9.2a Fairhope Al
PGIJon said:
Claude.. Please forgive my ignorance but could you please explain how I avoid side load. Do I just keep the belt loose?

Dan.. thank you for the insight. I'll do that.

Capt.. I already have mine coming from the Yanmar distributor here but I'll look into the Speed Seal. I would definitely prefer an o-ring seal.

Thanks all! -Jon
Click to expand
not claude but i think he means to make sure your belt alignment is straight on the pump pulley and that it has the proper tension if its out of alignment you may have to shim one way or the other with washers on the mounting bolts to achieve the alignment but more than likely it will be ok just use a straight line of site or a straight edge to make sure
 
kloudie1

kloudie1

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Nov 6, 2006
10,048
Hunter 34 Mandeville Louisiana
Jon, when you tighten the belt, it is best to push directly in-line with the belt if you can.. Seems like I remember that the handle of a hammer would prop on the big outer drive pulley on the engine and push pretty squarely on the pump pulley, allowing you to tighten the adjusting bolts.

EDIT: Ya beat me to it, Woody.. Yep, I agree That too.
 
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