A Unique Impellar Failure

[Bob_VT]

God bless my water pressure gauge on my dash. I was out last night and all of a sudden I had eratic water pressure..... then it went to 0 psi!!

I was near the ramp and took it home. At home I started the motor on muffs and no water.... shut it down (only ran for about 15 seconds).

Dropped the lower unit and expected to find the impellar in pieces and it looked perfect (it's only 1 month old). I was stumped!

After a nights rest I went back after it this morning.

I once again took apart the water pump to look for blockages. What I found was unique-

The impellar had failed on the inside on the shaft. There is evidence that it was slipping past the keyway and the keyway failed. You can see the slip marks inside the impellar

This was a mercury oem impellar.

I am happy I am running a dash gauge!

 

[Bob_VT]

Re: A Unique Impellar Failure

The good news -

It was warranted by the dealer and when he handed me the new impellar it was much heavier weight wise.

Since the failure I now have to re-do the decarb proceedure.

Bob

 

[Smig]

Re: A Unique Impellar Failure

Pardon the newbie question, but why do you have to decarb again??

 

[gss036]

Re: A Unique Impellar Failure

Obviously, the dealer had given you the wrong part. Bet he never even said, opps! sorry!? I wonder how a shop would have handled that, had they discovered it under the same circumstances? Who would have paid for the removal and replacement of the wrong part? Then we need to look at the liability of a blown engine had you not caught the mistake.

 

[Bob_VT]

Re: A Unique Impellar Failure

It was part of a complete water pump kit that was from Mercury Marine. I purchased the entire water pump however, the quality of the one in the kit is obviously lower.

Smig - since the motor got hot I checked my compression and it was lower across the board. ClamsCanino told me to decarb. They build up carbon as they heat and it is the safe thing to do. I have the sprays on hand, might as well do it right.

Bob

 

[ricksrster]

Re: A Unique Impellar Failure

Bob,
Do you think that:
1) the wrong impeller was packaged in the kit?
2) A bad impeller might have slipped through he QC inspection?
3) or Mercury really uses lower quality impellers in the kits, maybe to cut costs?

 

[Bob_VT]

Re: A Unique Impellar Failure

There is an absolute difference in the old and the new. The new one has a nice heavy brass bushing and the old one seemed much lighter. Then again maybe the spinning against the stainless key could have ripped the brass out of the old one. About a 2 ounce weight difference.

I already installed the new one (sorry I did not take pic's of it) and time will tell.

 

[Smig]

Re: A Unique Impellar Failure

I just replaced the impeller on my 850 with an OEM kit and it was like your first one - it looked like the hub was fiberglass. When I did my 500 last spring with a Sierra kit, it had the brass hub. Both seem to be working fine but I will definitly keep on eye out!

 

[jtexas]

Re: A Unique Impellar Failure

bob, wonder did you consider the possibility that you might have bent the vanes the wrong way on installation?

 

[Bob_VT]

Re: A Unique Impellar Failure

Jtexas - no. I always check the foward rotation of the drive shaft as I am installing the cover over the vanes on the water pump. I just think it failed due to a defect and yes Smig the first one I put in may have been fiberglass (looking back on it comparing the weight)