Changing A Raw Water Impeller

[Maine Sail]

Hi All,

I just changed my impeller and this time finally remembered my camera.

I've noticed a string of overheating threads popping up and thought this new photo based article on changing an impeller may help some who are not familiar or comfortable with the task.. To read and see the photos click on the links..

Changing A Raw Water Impeller
http://www.pbase.com/mainecruising/impeller

 

[Jim]

How do you get those o-rings to stay in the grove

when you put the plate back on. It aways falls off on me!

Darn Westerbeke and Universal. Wish I had a Yanmar again.

 

[Alan]

Easy

A little bit of grease.

 

[Maine Sail]

Jim I use...

Jim,

A PTFE/teflon based grease called Super-Lube and it's been enough to hold it in place long enough to get the cover plate back on.. I really like Super-Lube and use it on lots of boat things where I want to avoid a petroleum based product that may harm rubber. Super-Lube comes in a nice 3oz tube size that's perfect for the boat. It also works well for getting tight hoses onto hose barbs..

At first I worried about it eating or damaging o-rings or rubber but I've been using it long enough now to know that even in the long term it seems to be fine and the rubber or o-rings have shown no signs of damage.

Super-Lube Synthetic Grease
http://www.super-lube.com/synthetic-multipurpose-grease-ez-49.htm

 

[Bob]

Vasiline

I'm new to Boating this year. I bought my first boat, a Catalina 30. Unfortunately she is terribly lacking in battery AH which means I run my engine frequently. I made the rookie mistake of forgeting to open the sea cock. i replaced mine from the Westerbeke manual (Sherwood impeller). I was terribly frustrated because the o-ring didn't fit snug in the o-ring groove and I bought the kit from Hanson Marine "Westerbeke's suggested source. After 2 attempts I grabbed a jar of vasiline from the bathroom and coated the o-ring. It worked!

 

[Maine Sail]

Don't worry...

Quote: "I made the rookie mistake of forgetting to open the sea cock."


It's not just a rookie mistake!!! We all manage to forget that every now and then. I usually do it when I'm working on the engine and the key is in the ignition panel but I have closed the seacock while working.

If you leave the key chain on the closed seacock handle when you leave the boat you need to open the seacock, to get the key, to start the motor......

 

[Ken Palmer]

Excellent documentation

Tim, Nice job once again. As you may know, a link to your website is listed in a prime area on my home page. Keep up the good work.

Ken

 

[Pete]

The obvious question

is why you have had to change your impeller twice in a season? Are you sucking up sand or grit into the raw water pump? Is the water pump cover wearing out? This is not "normal" wear, IMHO. I normally get at least 2 seasons out of my impeller on my Yanmar and it I had to change them as often as you seem to be, I'd be on the hunt for the culprit.

 

[Tim R.]

Tim???

I hope you are not mixing up this clown with me ;-)

 

[Maine Sail]

In the article

it explains why I replaced it. I sucked in some weeds and had limited flow. This flow was not enough to cause my engine to over heat in the 10-15 minutes but enough to change the exhaust note and heat up the impeller due to limited flow.

Here's is the excerpt from the article where I describe it:

"So why is this impeller already cracked and ruined? That's an easy answer. We were motoring back in zero wind on a spring tide day. Spring tides have a nice feature that involves reaching far up onto the shoreline and pulling every last bit of seaweed and deposited junk back off the beach and into the bay. About a mile from our mooring I noticed the exhaust note change like less water was being spit out. I kept a close watch on my water temp and it only went up about 8-10 degrees above normal before we got to the mooring. The next day I went to the boat and I cleaned the strainer and reamed out the intake hose between the strainer and seacock. It was certainly restricting flow but it was NOT running totally dry, just less. Clearly it was enough to heat the impeller and damage it. As always, in a situation like this where it had limited flow, I check the impeller.
I was very surprised that only a few minutes of restricted flow caused this type of damage. Normally I would have stopped the boat and cleaned the strainer but the temp was not even at 190, it normally runs at 180, and we had a hungry baby on board so I pushed on."