View Full Version : 2000 Outback with a destroyed water pump impeller. Where did the squeegee pieces go?

03-29-2017, 11:34 PM
So I did a booboo and installed some waterlines backwards on the fresh water impeller pump. I had the IN/OUT water lines reversed after servicing. and didn't know it until AFTER I back into the lake first trip this year and start the engine.

2000 Moomba Outback
Indmar Assault 'GM/Chevy' 5.7L carb'd 325HP

First time in/year I like to let the engine warm a bit for a couple minutes - This year I noticed some extra noises coming from the impeller/pump due to it being run completely dry and with the water lines hooked up in-reverse. I also noticed some smells of burnt rubber probably also from the impeller, maybe from the exhaust heat.

I ran the engine for maybe 4 minutes total before I had really realized the fault but I do not think it overheated.

SO, my impeller pump completely lost all of it's squeegee fingers, and they are literally no where to be found.

Being the boat is 17 years old (but with only 250 hours); I figure its a great time to:
1. Replace the impeller and seals (duh)
2. Replace the engine's main water pump with new gaskets & sealer
3. Replace the thermostat with new gaskets & sealer
4. Replace a weak looking main water hose on the engine - main water pump intake side
5. Take off the upper exhaust housings and replace the square gasket / check for any rubber fingers (One of the gaskets had a very slow drip/leak last year anyway)

The boat is equipped with a heater.

I was thinking of running the garden hose through any hose AND the heater forwards and backwards to flush and back-flush anything I could. I feel if anything - the impeller parts are either somewhere between the hull's pickup and fresh water pump | stuck up in the engine water pump | stuck around the thermostat | Stuck in the upper/rear exhaust manifold | stuck in the heater | or stuck at the bottom of the lake.

Next time I'm planning to test start using a fake-a-lake engine flusher first.

Is there a filter/strainer or some kind of catch anywhere I may be missing?

03-30-2017, 08:26 PM
I found just a few pieces in the trainer cooler.

Removed the thermostat housings, water pump, exhaust water inlet hoses, Exhaust 'crossover' hoses, blew through the heater in reverse... Cant find the rest of the bits just yet.

Any help?

03-30-2017, 08:40 PM
I was just thinking (Read it on some truck forum just now) that to clear the block out it may actually benefit to run the engine without the thermostat for a few minutes. This would allow basically un-obstructed water flow through the engine; at which point anything stuck in the block's coolant passages may get ejected and thrown out the exhaust allowing the engine to get flushed out.

Maybe I should do this once at the lake before I remove the upper exhaust manifolds to clean them out by hand?


03-30-2017, 10:46 PM
If you hooked your lines up backwards the pieces should be in your intake line. How old is your impeller? Did you switch the lines then run the motor after the first event .... would explain pieces in cooler ( oh wait where is your cooler- before or after the impeller). How old was your impeller, maybe the pieces were gone before hand? Do you have a strainer.

You could also take the drain plugs completely out of the block then start the motor and your bilge pump, but don't sink the boat.

03-30-2017, 11:04 PM
Judging by the seal on the impeller housing the impeller was possibly never serviced. I don't think hardely anything has been off of this engine honestly as many items look original. I've only had the boat for 2 seasons and do not have any records of any service as I bought it from a dealer whom which received the boat from the original owner (Registration trail I do have). The original owner stored the boat in clean dry storage. I bought the boat with 200 hours on it and now it has 250 hours on it.

I do not know if the boat has a strainer though the inside of the tranny cooler does appear to be strainer-like. The tranny cooler is mid-way between the impeller and the pickup at hull's bottom.

03-31-2017, 01:58 AM
If you hooked them up backwards, then there was no water and there wouldn't really be any way for broken pieces to go anywhere. When I've had an impeller fail (with running water) the pieces either got caught by the transmission cooler, or were simply jammed in the ports of the raw water pump. Follow the hoses: any pieces pretty much have to be in the transmission cooler, the pump or the hoses between there and the main intake from the thru-hull. I guess I'd just hope that if anything got through the cooler than it would be small enough to pass through the water jacket.