When replacing the impeller in a raw water pump on a diesel engine, that is
sealed with a paper gasket, is it necessary to "paint" the gasket with silicone
or some other type of sealant when replacing the cover?

Also, I've heard that coating the impeller vanes with any kind of petroleum
based product, like Vaseline, ( to ease the installation) could cause the
neoprene vanes to swell or otherwise be damaged. Is this true? What about the
use of ordinary dishwashing liquid?

Also, I've heard that coating the impeller vanes with any kind of petroleum
based product, like Vaseline, ( to ease the installation) could cause the
neoprene vanes to swell or otherwise be damaged. Is this true? What about the
use of ordinary dishwashing liquid?

Teflon grease is the best choice for any rubber/neoprene parts in any
type of pump...'cuz it doesn't wash out very quickly and protects the
rubber from drying out when the boat sits. You can find it at most auto
parts and swimming pool supply stores

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/detai...=400&group=327

http://www.seaworthy.com/html/get_ri...oat_odors.html

On 30 Aug 2003 19:24:36 GMT, (Baybyter) wrote:

When replacing the impeller in a raw water pump on a diesel engine, that is
sealed with a paper gasket, is it necessary to "paint" the gasket with silicone
or some other type of sealant when replacing the cover?

That might be a good idea - can't see it doing much harm. (Though
silicones need to be "sensor-safe" types around exhaust manifolds and
preferably not the ones that evolve acetic acid either.)

Also, I've heard that coating the impeller vanes with any kind of petroleum
based product, like Vaseline, ( to ease the installation) could cause the
neoprene vanes to swell or otherwise be damaged. Is this true? What about the
use of ordinary dishwashing liquid?

Dishwashing liquid should be a good bet. I might even try a vegetable
oil - a smear of olive oil perhaps?

Brian W

Keith wrote:
I spray mine with silicone spray when installing. Also spray every
hose fitting before putting the hose on it.

Not a good choice for hose connections, Keith. You don't want to use
any lubricant that provides any lasting lubrication, 'cuz that can allow
the hose to work its way off the fitting. The only type of lubrication
that should be used on hose connections is one that's water soluble, and
therefore dries out and ceases to provide any lubrication very
quickly...dish soap or K-Y surgical jelly.

Otoh, pump parts that are "under water" for long periods require a
lubricant that doesn't dissolve in water easily, is thick enough to
provide protection against friction for a season or longer, and doesn't
have any petroleum products in it to degrade rubber...that's teflon
grease. Metal-to-metal parts require yet a different type of lubricant.

So the same is true of lubricants that's also true of sealants--there is
no "one size fits all" applications...you have to use the right one for
the particular job.

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/detai...=400&group=327

http://www.seaworthy.com/html/get_ri...oat_odors.html

Brian Whatcott wrote:

On 30 Aug 2003 19:24:36 GMT, (Baybyter) wrote:



When replacing the impeller in a raw water pump on a diesel engine, that is
sealed with a paper gasket, is it necessary to "paint" the gasket with silicone
or some other type of sealant when replacing the cover?



That might be a good idea - can't see it doing much harm.

Since the impeller depends upon close tolerance around the edges, I'd
not increase the thickness of the seal at all. Otherwise, your pump may
not work as well as you like. Just make sure the old one is all gone and
put the new one on. If pumps needed more than a paper gasket to work
properly, the manufacturers would sell them to you.

Also, I've heard that coating the impeller vanes with any kind of petroleum
based product, like Vaseline, ( to ease the installation) could cause the
neoprene vanes to swell or otherwise be damaged. Is this true? What about the
use of ordinary dishwashing liquid?



Dishwashing liquid should be a good bet. I might even try a vegetable
oil - a smear of olive oil perhaps?


Impellers are easy to install. A bit of spit would suffice for that. I
put a light oil in to ease the initial spin-up, expecting water to be
the primary lubricant after that.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

Pump parts, like impellers, that are under water are usually lubricated
by the water.

Ron

Ron Thornton wrote:
Nothing, thats why you do not run them more tha 30 seconds without water
coming out.

And why impellers require replacement at least every couple of years as
part of preventive maintenance...'cuz even a couple of seconds of dry
friction heat each time wears the edges of the vanes a little...it's not
something you can see just by looking, and there's only a microscopic
amount of difference between vanes that fit the housing tightly enough
to pump water and vanes that don't. Replacing 'em on a schedule
definitely beats being forced to do it when the pump quits...keep the
old one as an emergency spare--'cuz sand or debris can destroy even a
brand new one...applying some teflon grease when you install it helps it
last longer.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/detai...=400&group=327

http://www.seaworthy.com/html/get_ri...oat_odors.html

I bet you'de be hard pressed to find anything but trace elements of
teflon on an impeller after it has pumped water for an hour or so.
Lubricate if it makes you feel better but it really only makes assembly
a little easier. Beware what you use though, cause a lub with the wrong
solvents in it can damage it.

I agree with preventative maintenance being important because impeller
pumps are a cheap substitute for a better positive displacement pump.
The tolerances are not nearly in the micro range. That's why even with
the wide range of dimensions that comes from the plastic molded ones
driven by a drill, they still perform pretty well until they completely
wear out.

Ron

Ron Thornton wrote:
I bet you'de be hard pressed to find anything but trace elements of
teflon on an impeller after it has pumped water for an hour or so.


Silicone grease isn't worth a flip, but Teflon grease lasts quite a
while in marine toilets--at least a season, sometimes two--and swimming
pool pumps...so it should last in an impeller housing for a little
longer than an hour anyway. A new shot of it once a month or so
certainly wouldn't hurt.

Lubricate if it makes you feel better but it really only makes assembly
a little easier. Beware what you use though, cause a lub with the wrong
solvents in it can damage it.

Especially any petroleum based lubricant...for instance, vaseline or
WD-40.

Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://www.seaworthy.com/html/get_ri...oat_odors.html