Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-07-2020, 11:55 PM   #1
TF Site Team
 
Insequent's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 2,928
Engine impeller change frequency

I seem to recall discussions from time to time regarding the frequency of raw water pump impeller changes, but could not readily locate a thread on it.

For my starboard engine I have changed the raw water pump at 2 or 3 year intervals due to failed seals, and thus changed the impeller.

Yesterday, during a 2000 hr engine service when we did a lot of things 'whether they needed to be changed or not', we changed the port engine impeller. Its raw water pump seals had not leaked, and since the engine was always at normal temp I had not checked or replaced the impeller.

So the mechanic was just as curious as I was to see what it would look like after 7.5 years and 2000 hrs of use. The pic is below. Sure, one vane was gone but otherwise it was working fine. But we changed it anyway!
Attached Thumbnails
Click image for larger version

Name:	IMG_0525.jpg
Views:	89
Size:	59.6 KB
ID:	101202  
__________________
Advertisement

__________________
Brian
Insequent is online now   Reply With Quote
Old 04-08-2020, 12:41 AM   #2
Guru
 
Comodave's Avatar
 
City: Au Gres, MI
Country: US
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 9,450
I try to change mine every 3 years. They look almost new but do have a set to them. I would do it more often than 7+ years.
__________________

__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is offline   Reply With Quote
Old 04-08-2020, 01:51 AM   #3
Guru
 
Lepke's Avatar
 
City: Between Oregon and Alaska
Country: US
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 2,030
I pull my impellers at least once a year because I don't want them to come apart. I change the Detroit impellers at about 5 years. Generators a little sooner. If they have any cracks I change them.
Lepke is offline   Reply With Quote
Old 04-08-2020, 02:25 AM   #4
TF Site Team
 
Insequent's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 2,928
Quote:
Originally Posted by Comodave View Post
I try to change mine every 3 years. They look almost new but do have a set to them. I would do it more often than 7+ years.
I will likely do it more often in future. But if getting water flow from the exhaust and normal engine temps then perhaps checking rather than changing might be ok. I suspect I'll get seal failures way less than 7+ years in future. The seal failure for the other engine averages 2.5 years.
__________________
Brian
Insequent is online now   Reply With Quote
Old 04-08-2020, 03:57 AM   #5
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Country: USA
Vessel Name: Kinja
Vessel Model: American Tug 34 #116
Join Date: Oct 2017
Posts: 6,121
Gotta find those pieces!!! Blow back through the cooler!!!
On my NL gen., replaced the impeller because of failure. Blow back, MANY pieces. Perhaps the PO just replaced the impeller and never did the 'blow back' procedure. Way too many small pieces to come from only one impeller IMO
__________________
The meek will inherit the earth but, the brave will inherit the seas.
OldDan1943 is online now   Reply With Quote
Old 04-08-2020, 03:58 AM   #6
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Country: USA
Vessel Name: Kinja
Vessel Model: American Tug 34 #116
Join Date: Oct 2017
Posts: 6,121
I saw or heard, replace impellers annually, saving the one you took out for an emergency spare, if it looks good.
__________________
The meek will inherit the earth but, the brave will inherit the seas.
OldDan1943 is online now   Reply With Quote
Old 04-08-2020, 06:00 AM   #7
TF Site Team
 
Insequent's Avatar
 
City: Brisbane
Country: Australia
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 2,928
Quote:
Originally Posted by OldDan1943 View Post
Gotta find those pieces!!! Blow back through the cooler!!!
On my NL gen., replaced the impeller because of failure. Blow back, MANY pieces. Perhaps the PO just replaced the impeller and never did the 'blow back' procedure. Way too many small pieces to come from only one impeller IMO
Yes of course!

I did not fully explain. Part of the 2000 hr service was a barnacle buster flush of the heat exchangers, after which the HX end caps were removed, and replaced after a B Buster bath. As well as the impeller piece, and it pretty much was just one large piece there were a couple of bits of anode that had broken off when I was doing periodic checking of them.

I had tended to replace anodes after 2/3 was gone. But this meant that they were a bit crumbly or scaled up to a greater diameter than the threaded hole in the HX. Going forward I will be replacing anodes earlier, say once they are half gone.

Where I boat anodes last quite a long time, and when just buying the pencils to fit to the brass plugs the cost of early replacement is not that great. It will be better to have early replacement than to have pieces of broken anode in the end cap area where smaller pieces could subsequently block a HX tube.
__________________
Brian
Insequent is online now   Reply With Quote
Old 04-08-2020, 06:17 AM   #8
Senior Member
 
Beaverlake's Avatar
 
City: Sammamish
Country: US
Vessel Name: Knot Home
Vessel Model: Bayliner 4788 - 1998
Join Date: Jan 2020
Posts: 225
We run 200 hours +/- per year and change annually. I’ve got quite a few spares as a result but better safe etc. Cummins 5.9bta, 330 HP.
__________________
Patti & Gordon
Knot Home - 1998 Bayliner 4788
Anacortes WA
MMSI 368040370
Beaverlake is offline   Reply With Quote
Old 04-08-2020, 06:50 AM   #9
Guru
 
City: Rochester, NY
Country: USA
Vessel Name: Hour Glass
Vessel Model: Chris Craft Catalina 381
Join Date: Aug 2019
Posts: 2,259
I change every 2 - 3 years. If I go too long, I end up doing an emergency change during winterizing, as a slightly weak impeller will still seem to work fine until you feed it an air bubble while trying to pour antifreeze fast enough. Then it loses prime and that's that.
rslifkin is online now   Reply With Quote
Old 04-08-2020, 06:54 AM   #10
Guru
 
jleonard's Avatar
 
Join Date: Jun 2008
Posts: 4,000
I usually change every 2 seasons. They always look fine. I never keep an old one for a spare. I buy a replacement for the new one I just installed.
Knock on wood in 30 years of boating I have never had to flush out pieces of impeller.
__________________
Jay Leonard

New Port Richey,Fl
jleonard is offline   Reply With Quote
Old 04-08-2020, 07:07 AM   #11
Guru
 
Pete Meisinger's Avatar
 
City: Oconto, WI
Country: USA
Vessel Name: Best Alternative
Vessel Model: 36 Albin Aft Cabin
Join Date: Oct 2012
Posts: 1,472
Every two to three years of moderate usage. I don't know if salt is bad for impellers but since it's bad for everything else I assume it is not a friend of impellers. I am in fresh water, which is generally pretty cold, don't know if that has any effect either.

pete
Pete Meisinger is offline   Reply With Quote
Old 04-08-2020, 07:12 AM   #12
Guru
 
menzies's Avatar
 
City: Jacksonville
Country: USA
Vessel Name: SONAS
Vessel Model: Grand Alaskan 53
Join Date: May 2014
Posts: 6,922
Every Feb during the annual service (by the mechanic).
menzies is offline   Reply With Quote
Old 04-08-2020, 07:23 AM   #13
Veteran Member
 
Coastal Cruiser's Avatar
 
City: Atlantic coast
Country: United States
Vessel Model: Kadey Krogen 48
Join Date: Sep 2012
Posts: 70
Impellers work well, until they don't. I would not be comfortable running the boat with pieces of impeller vane partially blocking flow through the heat exchangers. We regularly run WOT and want the cooling functioning as designed.

Impellers are not expensive and, for most, changing is a DIY maintenance project. So for peace of mind I follow manufacturers recommendations:
-John Deere: 500 hours or annually, whichever comes first
-Northern Lights: 1000 hours or annually, whichever comes first
Coastal Cruiser is offline   Reply With Quote
Old 04-08-2020, 07:40 AM   #14
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Country: USA
Vessel Name: Kinja
Vessel Model: American Tug 34 #116
Join Date: Oct 2017
Posts: 6,121
Do you remove your impellers in the winter if you are on the hard?
__________________
The meek will inherit the earth but, the brave will inherit the seas.
OldDan1943 is online now   Reply With Quote
Old 04-08-2020, 07:46 AM   #15
Guru
 
City: Rochester, NY
Country: USA
Vessel Name: Hour Glass
Vessel Model: Chris Craft Catalina 381
Join Date: Aug 2019
Posts: 2,259
Quote:
Originally Posted by OldDan1943 View Post
Do you remove your impellers in the winter if you are on the hard?

Personally, I don't. Never heard of a good reason to. The antifreeze provides enough lube to keep them from sticking while sitting idle in the pumps and tearing on startup. Plus, on my engines, I have to pull the pumps to split them and get the impellers out, so if I were going to do that, I'd just change them every year.
rslifkin is online now   Reply With Quote
Old 04-08-2020, 09:08 AM   #16
Senior Member
 
tozz's Avatar
 
City: Seattle
Country: USA
Vessel Name: Conundrum
Vessel Model: Nordlund 63' Pilothouse
Join Date: Feb 2017
Posts: 222
Every year I replace impellers. 250-300 hours per year put on the engines. Have been told I could push to every other year but I simply like to avoid issues and err on the side of proactive maintenance.
tozz is offline   Reply With Quote
Old 04-08-2020, 11:00 AM   #17
Guru
 
Giggitoni's Avatar
 
City: Vallejo, California
Country: United States
Vessel Name: Mahalo Moi
Vessel Model: 1986 Grand Banks 42 Classic
Join Date: Jun 2008
Posts: 1,944
I believe it is Ted (O C Diver) that added a strainer between his raw-water pump and heat exchanger. His set up is designed to catch broken pieces of impeller before migrating to the heat exchanger, etc. Ted?
__________________
Ray
"Mahalo Moi"
1986 GB-42 Classic
ΜΟΛΩΝ ΛΑβΕ
Giggitoni is online now   Reply With Quote
Old 04-08-2020, 11:06 AM   #18
Guru
 
boathealer's Avatar
 
City: Out Cruisin'
Country: US
Vessel Name: SCOUT
Vessel Model: Great Harbour N37
Join Date: Aug 2017
Posts: 1,011
Quote:
Originally Posted by Giggitoni View Post
I believe it is Ted (O C Diver) that added a strainer between his raw-water pump and heat exchanger. His set up is designed to catch broken pieces of impeller before migrating to the heat exchanger, etc. Ted?
I did that recently based on Ted's photo. Full project writeup here: Raw Water Impeller Strainer
__________________
--
Ray
m/v SCOUT Web Site
m/v SCOUT Projects Page
boathealer is online now   Reply With Quote
Old 04-08-2020, 11:16 AM   #19
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 9,153
We do ours annually on our schedule. Having a single, itís not worth the risk for a 15 minute job plus I like working in a cool engine room while tied to the dock.
Larry M is offline   Reply With Quote
Old 04-08-2020, 11:57 AM   #20
Guru
 
Giggitoni's Avatar
 
City: Vallejo, California
Country: United States
Vessel Name: Mahalo Moi
Vessel Model: 1986 Grand Banks 42 Classic
Join Date: Jun 2008
Posts: 1,944
Quote:
Originally Posted by boathealer View Post
I did that recently based on Ted's photo. Full project writeup here: Raw Water Impeller Strainer
You and Ted are valuable assets to TF! You guys have designed my next project.
__________________

__________________
Ray
"Mahalo Moi"
1986 GB-42 Classic
ΜΟΛΩΝ ΛΑβΕ
Giggitoni is online now   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 05:22 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×