View source for Raw water pump, impellers and cooling system

= Raw Water Pump =

'''Model: Oberdorfer Pump 202M-15 (replaced by model N202M-15)'''

If your raw water pump starts to leak out of the weep hole of the pump chassis, it can rust out the engine mount and oil pan.

Rust damage from leaking raw water pump
[[Image:IMG 9251-MED.jpg]]

== Rebuilding An Oberdorfer Pump: ==

This is Ron Hill's Tech Note article from the May 2002 Mainsheet




If your raw water pump is leaking
water or oil from the weep hole in the
center of the pump body, a rebuild is in
order. If the oil side leak continues, you’ll
have a messy engine. If a salt-water leak
continues, it WILL rust out the oil pan!
The parts that you’ll need are two oil seals
(#10) Part # 295627. If the shaft has 500+
hours it will probably also need to be
replaced. Inspect the pump shaft (#6)Part #301788, and note if it is scored in the
oil seal area. For a more extensive rebuild,
you might need to replace the carbon
bushing if the shaft wobbles (#12) Part #302322.

[[Image:Oberdorfer_pump_diagram.JPG]]

Take the entire pump off the engine.
Remove the pump cover faceplate (#2)
and the impeller & pump shaft. If you
make yourself a special tool out of an old
1/4" Allen Hex Head Wrench, the job
will go much faster and easier. Cut the
short end of the hex wrench so it is only
9/16" long (outside tip to back). Then
grind down that tip until it is only 1/16"
thick and round off the corners of the tip.
Place the pump between two 2 x 4s with
the engine side of the pump facing down.
The 2 x 4s should be separated so the
center hole in the pump is between them.
Place the special tool on the top of the
lowest oil seal and tap on all four sides
with a hammer until it slides out. With
the lowest seal out, use the same procedure
on the upper oil seal. Although the
upper seal is called an oil seal, it really
keeps the water in the pump. The lower
seal keeps the oil in the engine. Be careful
not to damage the carbon bushing that
keeps the shaft centered. The special tool
tip should be short enough so you keep
from scoring the inside wall of the pump.

Before you replace the two oil seals,
clean and inspect the inside pump wall.
Apply a thin coating of "Permatex" #2
non-hardening gasket sealant. This
coating serves two purposes. First it will
seal any scratches (scores put in the wall
by a boat yard mechanic who rebuilt the
pump by beating the seals out with a
screwdriver!). It will also serve as a lubricant
to help the new seals slide in easier.

Turn the pump engine side up. Find
a socket that just fits inside the pump wall
(probably about a 3/4" size). When
replacing the seals, the lettering and
numbers should face each other. There are
two ways to reinstall the seals. One is by
pressing them with a vice (if you have a
Optional glass Optional "swinging" vice with a large enough opening) or
retainer pegs glass retainer tabs tapping them in with a hammer. Place the
first seal on the pump hole with the flat
side of the socket on the seal. Make sure
you use the largest socket that will match
the diameter of the seal so you don’t
damage the seal case. Then press or tap in
place. You want the seal toward the
impeller side to just go past the weep
holes (so it is easier to get out next time).
Then recoat with #2 "Permatex" and
install the second seal. The second seal
needs to go into the pump hole so it is in
solidly, but not all the way into the weep
hole area.
When reassembling the pump, don’t
forget to inspect the pump cover (faceplate)
for grooves made by the impeller.
Take the faceplate and use some wet #400
sandpaper on a flat surface and smooth
out the ridges. You can also take the cover
to a machine shop and they will reface it
for you for about $5. If you take it to a
machine shop, have them do both sides of
the plate. That way the next time all you
have to do is turn the plate around and
you’re ready to go. Finally, reinstall the
faceplate with a PAPERTHIN gasket (#3)
Part # 295626. . Use a thicker gasket and
you won’t have an efficient pump and the
temperature will probably go up. I haven’t
tried my tool on a Sherwood pump, but
I’m sure that it will also facilitate in its
rebuild. —Ron Hill APACHE #788


Contact Depco at (800) 445-1656 for ordering replacement parts.

Seal removal tool
[[Image:Oberdorfer_rebuild_tool.JPG]]

Installing Seals using a vice as a press
[[Image:Oberdorfer_Seal_install.JPG]]

NOTE:  There is a post on the Main Message Board with additional pictures:  http://c34.org/bbs/index.php/topic,6766.0.html   [Stu - 10/19/2013]

= Impellers =

= Cooling System =