No water through exhaust

[SATige]

I had my 2002 21v (Merc Mag) on the hose today and I wasn't getting any water out of the exhaust, I didn't allow it to overheat but the exhaust risers were getting hot. I just installed a new impeller, other than that nothing has changed. I pulled the lower (supply side) drain plug out of the impeller housing while running, and cold water rushed out proving water was getting there. Any ideas why the water isn't getting out the exhaust?

[lee]

Was the blocked drained for winter? How long did you run the engine?

[SATige]

Yes, it was drained. I ran it long enough, the temp on the gauge was exceeding 175 and I shut it down.

[NICKYPOO]

Was the previous impeller blown? Are you sure the new one didn't blow when you started it. If you put it in backwards, this can easily happen. I've had a new one blow fresh out of the bag. Did you replace the pump body? I'd be pulling it apart straight away.

[SATige]

Nicky, The old pump wasn't blown, the body is two yeas old. I agree, I need to pull the pump out, I never considered that a new impeller could detonate.

[lee]

Did the intake and the exhaust hose get crossed?

[SATige]

Lee, I looked at that last night, it appears the intake port to the pump body is smaller than the exhaust port and the hoses are different sizes. I don't think they could get switched.

[NICKYPOO]

I'm guessing you are checking now but also make sure that the pump is actually spinning. I've had a new impeller not spin when the motor started. It should make an awful screeching noise from the belt rubbing across the "frozen" pully if that is the case though.

[SATige]

The impeller was fine the veins will flip over depending on the direction that you turn the pulley. I'm lost. There is an automotive style water pump on this motor as well, could that be related to the problem I'm having?

[NICKYPOO]

I would never trust the veins to just flip over. I always install so that they are the correct direction.

That's the recirculating pump. Is it spinning?

Wait! There are two different impellers that look nearly identical except for the very center. Does your new impeller have the flat spot on the center where it slides onto the pully? If it doesn't, it ain't gonna spin.

[SATige]

You are correct to not trust the veins to just flip over on their own. I believe that was the problem I had. I hand rotated the pump and the veins flipped over in the opposite direction, I then re-installed the pump and now it's working fine. Thanks for all the help and ideas!ImageUploadedByTapatalk1459016678.232747.jpg

[NICKYPOO]

I'm just glad it's working for you. Always a great feeling when it comes back to life.

[ChrisSnow]

The veins will flip on their own. I'd be concerned you may still have an issue if that's all you changed.

Check for air leaks.

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[NICKYPOO]

Wait! There are two different impellers that look nearly identical except for the very center. Does your new impeller have the flat spot on the center where it slides onto the pully? If it doesn't, it ain't gonna spin.

This is wrong. The other type has two flat spots on the hub. That is why it won't work if you need the single. Sorry about that. Brain fade I guess.

[SATige]

This is wrong. The other type has two flat spots on the hub. That is why it won't work if you need the single. Sorry about that. Brain fade I guess.

I actually had the same thought initially, but by turning the pump by hand confirmed that the impeller was engaged with the shaft.