changed impeller 87 cobra outdrive

[jclenik]

Hello,

I changed the impeller in my 87 cobra outdrive and when I went to test it there is water shooting out the back of the pump housing thru a hole.
Is this normal or do I need a new housing?

Thanks

 

[a70eliminator]

Re: changed impeller 87 cobra outdrive

I don't think that is normal, the pump housing has a vent tube and i believe that is the only place water will escape, observe it with the plastic cover off and see exactly where it's comming from. The vent should have a plastic tube attached leading into the lower drive unit cavity.

 

[stevea661]

Re: changed impeller 87 cobra outdrive

My old pump housing didn't have a barbed fitting, just a hole and the water squirted out of there. When I replaced it, the new one had the fitting so I also got the hose, connected it to the housing and routed it into the outdrive, under the cover that covers the impeller housing. either way it worked. The thing to remember is that the new metal sleeve needs to be glued into the plastic housing with aviation gasket sealer. Otherwise it will spin, ruining the new housing and causing the engine to heat up. Don't ask how I know

 

[sea wolf]

Re: changed impeller 87 cobra outdrive

Hello,

I changed the impeller in my 87 cobra outdrive and when I went to test it there is water shooting out the back of the pump housing thru a hole.
Is this normal or do I need a new housing?

Thanks

It's normal. Not all Cobra's have the vent hose, mine doesn't. And I've never heard of gluing the metal sleeve to the pump housing. How 'ya gonna remove it if it's cemented in place?

 

[stevea661]

Re: changed impeller 87 cobra outdrive

It's normal. Not all Cobra's have the vent hose, mine doesn't. And I've never heard of gluing the metal sleeve to the pump housing. How 'ya gonna remove it if it's cemented in place?

OMC cobra manual 1986, revision 1, page 7-20, item # 4, pic 97 says, sparling apply OMC gasket sealing compound to the interior walls of the impeller housing where the liner makes contact. Item 5, pic 98, says push the housing into the hole until it seats, wipe out any sealer that may squeeze into the liner through the water slots. This is what the manual says to do with the sleeve and the housing. I didn't do this with mine the first time, because I didn't read the manual. After the sleeve rotated, ate the impeller, melted the housing, got the engine warm, and ruined my day on the water, I looked in the manual to figure out what went wrong. What went wrong is I didn't do it right the first time. Just trying to offer some time saving advice.

 

[cr2k]

Re: changed impeller 87 cobra outdrive

I guess, but OMC gasket sealing compound is not an adhesive. In fact it is often used to "lube" parts going together like O-Rings. Often using and after market housing and OEM cage or visa-versa you will have that kind of problem due to slight tolerance issues.

 

[stevea661]

Re: changed impeller 87 cobra outdrive

I guess, but OMC gasket sealing compound is not an adhesive. In fact it is often used to "lube" parts going together like O-Rings. Often using and after market housing and OEM cage or visa-versa you will have that kind of problem due to slight tolerance issues.

Google omc gasket sealing compound. It's an adhesive. Similar to permitex aviation gasket sealer. And for OMC all there is, is after market.