MMI FWC Kit Raw water pump pulley alignment

[Mike Hall]

Update 9/11/2011 - As hard as I try I cannot get the pulley that drives the raw water pump to align with the PTO pulley on the fly wheel. As a result, the raw water pulley wobbles - creating enough imbalance and vibration to cause scoring on the shaft by the pins holding the pulley. I know the manual for the MMI FWC kit said it isn't necessary to get them to line up exacty. It's lined up with the PTO pulley, but there is a noticable difference in the angle of the pulleys.

I decided to scrape the whole thing for now because the noise is intolerable and I'm concerned about damaging the pump and the system failing. So farr I can't find where anyone has had difficulty with the system. What am I doing wrong?

[ndutton]

As a result, the raw water pulley wobbles -

A misalignment wouldn't result in a wobble. I think you either have a bent pump shaft or a bent pulley.

[Mike Hall]

Thanks Neil, I was already considering a new shaft because of the scoring on the original one. Might as well get a new pulley as well. I'm also wondering if it's a problem with the PTO pulley (although it seems balanced) or maybe the pump bracket that bolts to the starter.

[ndutton]

The fact the pulley does not run true tells me it's not a bracket problem. How about some video??

[Mike Hall]

Too late, I already removed the pump and reverted back to raw water cooling. But it wouldn't take much to reinstall.

[ndutton]

Clamp the pump with pulley to the bench, hold a square on the bench top and pulley face and turn the pump by hand. I bet the problem will reveal itself. You might have to block up the pump base to gain pulley clearance.

[Mike Hall]

Thanks - since i removed the pump and bracket I can run the test quickly and easily. will let you know what I find. The MMI install manual suggested that the bracket may need bending in a vice to get better alignment.

Question - let's assume the pulley is fine - if the PTO pulley is at a 3 degree angle and the pump pulley is mounted at a 2 degree angle, would that cause the wobble?

[Mike Hall]

I also notice that the pulley doesn't fit snuggly on the shaft. There is noticable play. The 2 pins provided for the pulley don't give me a lot of confidence and actually seem to be moving around enough to cause scoring on the shaft.

[ndutton]

Question - let's assume the pulley is fine - if the PTO pulley is at a 3 degree angle and the pump pulley is mounted at a 2 degree angle, would that cause the wobble?

No.

Both pulleys should run true (no wobble) but the misalignment would wear the sides of the belt and produce black belt dust all over the place.

I REALLY have a problem associating the bracket with wobble. The wobble is rotational, the bracket is stationary.

edit:
noticeable pulley play could be it. Note that my FWC is electric, no PTO pulley and extra pump so I'm talking on principles here rather than direct experience.

[Mike Hall]

I did see some belt dust, but not much. Think I may try a new pulley and check with MMI to see if I can add some sort of bearing to eliminate any play. What type of electric pump do you use?

[ndutton]

What type of electric pump do you use?

Here are the two threads that discussed it in detail:

http://www.moyermarine.com/forums/showthread.php?t=5008

http://www.moyermarine.com/forums/showthread.php?t=4778

(posts from #99 on really get into it)

To summarize though, the popular electric pump is the rather expensive Johnson CM-30. I used a Ford Mustang supercharger intercooler pump at 1/4 the price and 7% less flow. So far so good.

[Mike Hall]

Good stuff. Since I've already spent the money on the mechanical pump, I'll try to make it work first but it's good to know there is an alternative.