Decided to replace the impeller. After wrestling with the cover plate screws, noted that housing surface needed some cleaning up. Then noticed that there is an adjustable bearing in the impeller housing on a setscrew. I wonder if anyone knows what the specs on the bearing should be, and how one adjusts it.
2GM20F Water Pump
- Thread starter wufibugs
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I have not ever messed with the set screw (maybe never noticed it either).
I have struggled with the screws on the cover plate. My final task with them was to replace the cover plate with a Speed Seal. They have a heavy duty cover with thumb nuts that make r/r the impeller much quicker.
I have struggled with the screws on the cover plate. My final task with them was to replace the cover plate with a Speed Seal. They have a heavy duty cover with thumb nuts that make r/r the impeller much quicker.
Now that I'm looking more closely at it, Steve, I see that the hole in the housing is not threaded, and it is somewhat larger than the set screw itself, which threads into the bearing. So what keeps water froem leaking past he bearing and up through the set screw hole? I did not see any small gasket or o-ring beneath the set screw head. The set screw itself broke when I unscrewed it, so I will need another.
If you are talking about the cam retaining screw, there is no adjustment it is just a retaining screw. How did it break? If it came out clean form the cam it is just a matter of replacing the screw. The pressure holding the screw head to the pump body prevents water from leaking out. There is no maintenance involved with that screw and it is just removed when taking out the shaft to replace bearings and seals.
I think that Benny is right.
The attached picture is of a fairly standard Oberdorfer water pump. The screw that is between the intake and output side of the pump likely just holds the cam/shoe in place. Without that screw the pump will leak and not work very well. It should be kept tightened such that no water weeps out. There should be a drain plug on the bottom of the pump body for draining water come winter layup. Neither of these screws need to be used to replace the impeller, only the back plate screws.
If you take the back cover off and have a look inside it will be more clear what it going on inside.
The attached picture is of a fairly standard Oberdorfer water pump. The screw that is between the intake and output side of the pump likely just holds the cam/shoe in place. Without that screw the pump will leak and not work very well. It should be kept tightened such that no water weeps out. There should be a drain plug on the bottom of the pump body for draining water come winter layup. Neither of these screws need to be used to replace the impeller, only the back plate screws.
If you take the back cover off and have a look inside it will be more clear what it going on inside.
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Just to make sure we are talking about the same thing, and I think we are, I took a few pictures. Pump1 is of the hole where the cam retaining screw enters the pump body. Pump2 shows the interior of the pump without the cam. Pump3 is of the cam alone. Pump4 is the cam in place in the pump body. As I said, the cam is threaded on the backside; the pump housing is not. Since the screw broke off and had to be drilled out, I am not sure of the length of the original. And since it must be screwed in till it stops, the length is crucial. Is there a source for the length of that screw?
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you might want to use a match stick as a dept gage .....just put the two parts together like they are intinded and put a match stick in the screw hole ,,,,marking it with your thumb nail and then holding that mark up to a steel 6" scale and measuring the length....then find a round head machine brass/ss screw 1/32 of an inch shorter than the measurment and in stall it .....
regards
woody
regards
woody
I suggest you either take your water pump to a Yanmar dealer and try to find the part there, or contact Torresen, Marine Diesel Direct and discuss your need with them. Very helpful people.
http://shop.torresen.com/marine_diesel_direct/Yanmar/
or
Torresen Marine, Inc.
3003 Lake Shore Drive - Muskegon, Michigan 49441
Phone: 231-759-8596 - Fax: 231-755-1522
http://shop.torresen.com/marine_diesel_direct/Yanmar/
or
Torresen Marine, Inc.
3003 Lake Shore Drive - Muskegon, Michigan 49441
Phone: 231-759-8596 - Fax: 231-755-1522
There are two different brands of pump used on the 2gm20f. One is on the Japanese buit Yanmar, and the other on the european buit version. The pump on the euro verson is a Swedish manufacture and uses an entirely different impeller.
The threaded rod in that impeller doesn't do anything but sit in the groove in the impeller shaft.
I've found the easiest way to change the impeller is to disconnect the entire pump. Its far easier to get at the screws on the plate. By the way, the euro version pump has an "o" ring seal rather than a gasket.
The threaded rod in that impeller doesn't do anything but sit in the groove in the impeller shaft.
I've found the easiest way to change the impeller is to disconnect the entire pump. Its far easier to get at the screws on the plate. By the way, the euro version pump has an "o" ring seal rather than a gasket.
Moyer Marine also sells the cam shoe screw for the Oberdorfer model pumps: http://www.moyermarine.com/cgi-bin/...all&template=Templates/B000_storebuilder.html
The screw has a small rubber washer under the head and they are expensive as screws go.
The screw has a small rubber washer under the head and they are expensive as screws go.
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If Doug is correct, mine is the Asian version since it uses a paper gasket under the impeller housing cover. If I used a standard brass screw measured roughly as Woodster suggests, I would probably put a little gasket sealing along the screw to seal both the housing and beneath the screw head much as does the rubber washer Caleb describes. Since I need the impeller and gasket, I will see how exensive the OEM set screw and cover screws are. Do folks usually put a little anti-sieze on the cover screw threads?
wufi, some P/Ns and costs for the raw water pump parts.
A. Qty. 1 Raw Water Pump COVER Yanmar P/N 121575-42150 at $10.25
B. Qty. 1 Raw Water Pump Cover GASKET Yanmar P/N 124223-42110 at $2.75
C. Qty. 6 Raw Water Pump Cover SCREWS Yanmar P/N S/6 26544-040082 at $0.50 ea. (1 set at $3.00)
D. Qty 1 Raw Water Pump IMPELLER Yanmar P/N 124223-42092 at $34.50
These are all for the Raw Water Pump on the Yanmar 2GM20F engine.
A. Qty. 1 Raw Water Pump COVER Yanmar P/N 121575-42150 at $10.25
B. Qty. 1 Raw Water Pump Cover GASKET Yanmar P/N 124223-42110 at $2.75
C. Qty. 6 Raw Water Pump Cover SCREWS Yanmar P/N S/6 26544-040082 at $0.50 ea. (1 set at $3.00)
D. Qty 1 Raw Water Pump IMPELLER Yanmar P/N 124223-42092 at $34.50
These are all for the Raw Water Pump on the Yanmar 2GM20F engine.
Go to a Yanmar dealer and order the part. The screw will come in the correct length and thread pattern. The price of the screw will be insignificant compared to the impeller and gasket. Check the pump and if there are any worn parts this is the time to replace those.
wufi ...that is the best thing to do ....i assumed you only needed the screw...but as you need the other parts as well then you can also get the screw along on that order .......then you will have OEM all the way....
regards
woody
The cam retaining screw is listed as part #26554-040102 Screw M 4 X 10 $0.94. I would not risk trying to match it at a hardware store.
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