Impeller housing

[Jongleur]

A couple of impeller questions: Why were 2 bolts longer
than the other 2 bolts on my oberdorfer impeller
housing? Couldn't figure out where they had to
go back in, so I put the longer ones on the
bottom for no good reason.

Why was there no gasket? It was the first time
I changed this impeller since I bought the boat.

How hard is it to put the impeller shaft back in
if I accidently pull it out? The guy at the diesel
place said they pull the shafts out routinely and
they goe right back in. The manual says follow
a critical sequence to reinstall the shaft.
I wondered, because it was a bear(!) to put on
that little retaining ring, even after I bought a
$25 tool to splay it. If the shaft were pulled
out, the ring could be easily put on.

 

[Anonymous 121765]

Jong,

If you pull the shaft out accidently (it happens), Don't fret as the shaft is keyed so you can rotate it to find the flat side in the shaft hole. If an Oberdorfer pump, there is a paper-thin gasket that comes with the impeller. You NEED this gasket.

When installing, take some Vaseline or a machine oil & grease up the impeller & inside housing first, it will be easier to install. Careful not to damage the impeller. You will need to bend some vanes that fall on the raised section of the inside housing while installing.

CR

 

[Donnybrook]

Are you talking about the screws on the cover plate or the bolts that hold the pump to the engine? The newer Oberdorfer pumps use an O ring on the cover plate, so no gasket is required. The shaft fits in a slot inside the engine. If it is not all the way in, the impeller will not go all the way into the housing. If the shaft is not all the way in the slot, push in on the shaft while slowly and carefully rotating the engine by hand. It will drop in the slot. Most people don't put the retaining ring on, as it really serves no purpose.

 

[Anonymous 121765]

Donny,

Jong never mentioned the age of his engine nor the impeller pump he has. The older pumps used a paper gasket, the newer ones use an O-ring. Not knowing what he had, I only offered a general approach for his changeout.

He did state there was NO gasket, he never spoke of an O-ring. I guess we need wait to see what he has.

CR

 

[Jack - La Paz Mx]

Might as well jump in on this....the impeller vanes are bent only one way as they cross over the "hump" in the housing. The direction of bending is opposite the rotation of the shaft when running. Bending them as you push the impeller into the housing is easiest (with lubricant...which also lubricates the impeller as the engine is started until water flows into the housing).

 

[Jongleur]

The engine is an early '80s. I'm talking about
the cover plates 4 little bolts that are 2 different
sizes.

The PO did not have a paper thin gasket there
but I did find paper remnants. It was barely
leaking.

The diesel place said to only use vegetable oil
or dishwashing liquid on the vanes.

Is it true that most people don't put on the
little ring clip????

 

[Anonymous 121765]

Jong,

Thanks to Jack, he filled in more info for you to keep in mind. I don't know about the different size bolts tough.

Best to take a pic. My boat is a 1980. It came with the old 5411 Universal. It had an Oberdorfer pump. My newer 3M20A had a Sherwood pump which is by design, meant to fail. Two in the first three years then, I got an Oberdorfer.

How did you get the correct impeller? You never mentioned what pump you have.

CR

 

[Jongleur]

Spent some time working on the boat. Here's pix
of the impeller.

 

[Anonymous 121765]

Jong,

This looks like an Oberdorfer pump. Don't worry about the different length screws. Do they work for attaching the cover plate, if so It may not matter. Was it an Oberdorfer impeller you ordered, if so it should have a paper thin gasket. If not, you can make one yourself (I did once & it worked up to the next changeout, it's in compression, it's not going anywhere). Take a brown paper bag & mimic the shape, but make sure it only covers the outer flange area on the cover plate, for you don't want to impede on the impeller.

Maybe, the PO lost the original screws on a changeout & picked up two from a hardware store that were alittle longer.

CR