Logo
FULL SITE MENU

Help please! 1982 25 hp

T

the_beave

Member
I replaced the impeller on my 82 Mariner 25M today and when I started it up there was still no water pumping thru! I dropped the lower unit again and tried putting water up the pipe and it went up and came out no problem! Then I sprayed water into the pump thru the water oulet and water came out no problem! So then I took the water pump apart again and found that my new $45 impeller had disintegrated! What the hell could have caused this? The inside of the housing looks ok and feels ok!
 
Re: Help please!

Maybe your water pick-up is clogged solid - so if no water was getting to the water pump, the impeller would have "eaten itself"...
 
Re: Help please!

it turns out that the owner before me, or someone "fixing it for him" has tried to, I guess, repair the pump housing or something! It must have come apart! The cover is plastic with a metal liner inside where the impeller itself goes! The metal piece was in wrong and there was a real mess of epoxy that had almost blocked off the water passage and the way the metal piece was in was restricting water flow as well! Now I just have to find out if the metal piece should be flush with the plastic or sticking out beond it like it is now! I'm thinking it should be flush!
 
Re: Help please!

Yes, it needs to be flush - when you torque down the waterpump, that plastic cover should make contact with the lower plate - the metal cup can touch as well but it should not prevent the plastic from making contact.

There is sometimes an o-ring between the cup and the cover (around the hole where the driveshaft comes through the pair) and it would be normal to put a few small dabs of silicon there to hold the ring in place until the two components are pressed together - but there is also an (air bleed) grove there that allows the pump to prime itself. If it's obstructed that could have well caused your chewed "new" impeller.

You should really tear it all down and get some OEM replacement parts.

I like Sierra parts for alot of things (and while I don't know if the cup is a Sierra part in this case), I have never found one of their cups which wasn't just a little too big to fit the cover properly - so for waterpump parts I always go OEM unless it is absolutely not available.

Merc part 95661T is a complete new assembly (cover, cup, seals, plate, gasket, impeller and bolts). It is pricey (130 retail), but could save you countless headaches...
 
Back
Top