Impeller 2005 Centurion C4 Cyclone

Whats up peeps...I'll cut to the chase. Changed out the impeller, cranked the engine to test pump and heat the oil to change it out. No water...no water...no water. Shut it down. Adjusted the flusher cranked a little more water from the garden hose. Restarted and still no water. I thought to myself "well you're pretty stupid, I'm sure you put the impeller in backwards". So I again did the awesome task of removing the impeller housing. After taking it apart I matched a picture of the old impeller to the new one and the new one seems to be smaller. The tabs aren't as bent. What am i doing wrong here??? Do i have the wrong impeller? No water in the boat, hoses are not leaking. It just isn't pumping. 18-3016-1 impeller kit to replace 47-862232A2. 350 MAG Mercruiser

Looks good to me.




Not to be a stooge. Did you open or shut the main ball valve before winterization?



Do you know the pump is actually spinning ( hear it /feel it). Maybe punpmis stripped or went bad.

The veins spin when i turn the wheel and i got down in the locker to make sure the wheel was spinning. I don't really winterize my boat as I live in Miss and it stays in a heated building. (i can feel the wakeworlders preparing to pounce) I clean it, pump it full of stabil, change the oil and fog it for its hibernation. I change the impeller every winter and have never had this problem.

fyi...you can't put an impeller in backwards. the impellers will flip over as needed.

Did you hook the hoses back up correct to the pump?

Scottb7, I really didn't know that, but does make sense.

Truekaotik there only one way. Different size hoses and openings. Yes big hose would fit on the little but no way little hose would fit on the big. No water in hull so hose clamps and connections must be good

I'll reassemble and give it another go when time permits.

When running on a hose with a brand new impeller I've had to give mine just a little throttle to get the pump back working. Almost like it needed primed or like the impeller was really tight at first and not spinning. Push the button in on the throttle so you don't spin the prop and are just increasing rpm a little bit. Happened twice on my '06 Supra. I increased the rpm's up to maybe 1100 very briefly and all started working again fine. Could have just been coincidence but it seemed to work.

If everything is hooked up right and it is for sure spinning, not slipping.
A couple more things to check..
It's not priming due to insufficient pressure and water. Throttling may help or make it worse, be careful or prime everything(take hose off top of motor and fill both ways.) with water first, then try it.
The wear plate in the pumps other half is worn enough it's not pumping efficiently anymore and the cheesy garden hose is showing you the fault. Check wear plate.

You can also have a blockage farther in the system that's causing very high backpressure the pump can't overcome with a garden hose. Check your vdrive strainer to start...
You can remove the outlet hose on the water pump to make sure it pumps right and visually see it come out the other side first, then move on..
These are guesses as I am not there..

Baggar55 I will try that. But I may need a prozac putting any revs into an engine knowing it doesn't have coolant.

Truekaotik is the "wear plate" the other half of the pump housing that closes the impeller in?
I will fill the hoses with as much water as possible.
Will check the strainer.
As far as the garden hose...wouldn't a garden hose have more pressure forcing water into the pump than the boat floating in water having to suck it up from the bottom?

You don't need to rev it hard or for very long. The engine won't be hot enough to hurt anything right when you start it up. Just gently add some revs to the motor to build and stronger suction with the pump. Maybe a quick little rev and the impeller will spin and pump will prime. If it doesn't work right away you have another issue. You will know very quickly if it worked.

Thanks guys. Filled hoses, put some revs to it and worked like it's supposed to.

" But I may need a prozac putting any revs into an engine knowing it doesn't have coolant."

Be reminded that the engine is cold so no worries, and the engine oil is still pumping when engine is running. The only thing that gets ruined is that that impeller will get wrecked if you run too long with no lube from water.

Scott