Cobaltchat.com

AsLan7 wrote: ↑Wed Aug 16, 2017 1:52 pm

cmattj wrote: ↑Wed Aug 16, 2017 1:37 pm Merc 496 fresh water pumps with wear can leave a edge on the face plate that when a new impeller get installed the fear is it cavates or is ineffective at higher speeds with all the groves on the pump side out.

Its common with most cast pumps that have had an impeller fail or just wear on the end plate. Most shops recomment replace the complete unit and with your closed cooling system that is $$ as the 496 merc closed cooling have air dump winterizing pop off lines and sensors and are more complex.

My fix is I have that top wear plate machined down (yes it gets thinner) but its ok as it still bolts down and seals. cost $30.00 bucks. and all the stock merc impeller kit work fine.

If the inside housing gets worn wich is less common then you throw it away. Ive never like those kits that come with shims and reduced impellers as I would just go after market at that point..

Stll an easy fix.. dont throw it away untill you inspect it. Boatmasters here in livermore, ca has them on the shelf ready to exchange.

Great info Matt! Thank you.

When you say "you do not like the kits/reduced impellers/shims, etc"....this is not the same as the entire housing that is sold on the performance link above, correct? What are your thoughts on those "improved" sea pump housings?

I'm just curious if my possible lack of water pressure (which I believe to be the case) on plane is causing the alarm to sound because the new impeller and new tube thru the gimbal which carries the water cannot keep up while on plane due to housing wear. Hoping the marine tech can confirm this issue.