Impeller Rotation Question

[nate844]

So I'm in the process of changing the impeller in my 2003 Bayliner with a 3.0 Mercruiser Alpha One. When I removed the old impeller, the vanes seemed (to me) to be rotating in the wrong direction. Can anyone help explain this to me???

Pics are attached..:

 

[Bt Doctur]

If you hold the housing in your right hand, and using your left hand to install the impeller, you twist the impeller counter clockwise while pushing it into the housing.
Your drive is an Alpha 1 GEN II drive.

 

[nate844]

Right. But if I did that, it would be opposite to what the one I just took out looks like...right? Hence my confusion.

 

[Scott Danforth]

When you key off, does your motor run on a bit? If so, your motor most likely ran backwards for a few revolutions.

 

[nate844]

It does have an issue with "dieseling" on occasion. I didn't realize when it did that the motor was running backwards. Thanks for the info!

 

[Scott Danforth]

that last gasp as the motor runs on just before stopping is it sucking water from the exhaust into the cylinders. make sure to take care of the run-on - you may want to check your timing. if it continues to run-on, shut off while in gear.

 

[mr 88]

I could be wrong. I would think any rubber impeller set up like that would have the vanes automatically put in the correct position once the shaft started spinning regardless of how it was installed.

 

[achris]

I could be wrong. I would think any rubber impeller set up like that would have the vanes automatically put in the correct position once the shaft started spinning regardless of how it was installed.

Correct. And once the engine is running the vanes flip the right way round. The problem is when the engine is shut off, its last gasp is a backwards kick, they all do it... That can flip some of the vanes around... It's ok, because the next time the engine starts they sort themselves out again. The problem is if the engine continues to run backwards, it sucks water in through the exhaust....

Chris....

 

[nate844]

Thanks so much for the replys. I installed by spinning the shaft clockwise and pushing down on the housing. Hooked it up to the muffs and everything seems to be running fine. Thanks again!