Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 18-02-2020, 22:38   #1
Registered User

Join Date: Sep 2012
Location: Now NZ after Med, Middle East, SE Asia, UK
Boat: Moody Carbineer 52
Posts: 102
How can I back flush an engine (Perkins 4-236 in particular)?

Forumites;
Can someone advise me on how to back flush my Perkins 4-236? Do I need to make up some special connection in order to attach a standard garden-hose type connector to a particular orifice low down on my engine (which orifice??!!)?
After having a flush by competent engineers last year, now my coolant contains rust so I think it needs a serious back flush, not just the usual run through with a standard flushing agent and a couple of rinsings.
(My port engine has been treated just the same as the stbd one, and has nice clean green coolant; both engines run at similar temps and oil pressure, so I have no idea that there is any particular problem with this engine, am hoping it just needs a really good flush....).
Thanks!
__________________

keithw88 is offline   Reply With Quote
Old 19-02-2020, 07:26   #2
Registered User
 
svHyLyte's Avatar

Join Date: Mar 2006
Location: Tampa Bay area, USA
Boat: Beneteau First 42
Posts: 3,933
Images: 25
Re: How can I back flush an engine (Perkins 4-236 in particular)?

Disconnect the hose from the water pump">raw water pump to the engine on the discharge side and disconnect the hose from the discharge side of the heat exchanger that connects to the injection nozzle. Make a temporary hose connection to your fresh water source to the hose "from" the heat exchanger; and, a temporary hose connection to the hose on the discharge side of the raw water pump (to the engine) which will be the discharge from the back-flow exercise. Direct that to a bucket to capture the back flow. Start your back-flow "gently" keeping in mind that shoe side water may be at 40PSI or better. Flush until the discharge into the bucket seems to run clear.

Once that's done, make up a solution of Barnacle Buster and fresh water in your bucket and attach the discharge hose from a small submersible bilge pump, submerged in the bucket solution, to the discharge line from the heat exchanger in place of the fresh water hose from shore side. You can power the pump with alligator clips temporarily connected to your batteries. With that, let the solution "back flow" through your heat exchanger for a couple of hours. You may be astonished at the amount of gunk that will be released. (Put the pump in the foot of a woman's nylon stocking to "filter" the solution going back into the heat exchanger.)

Once that's done, reflush the system with fresh water and then restore the original connections and you're good to go.
FWIW...
__________________

__________________
"It is not so much for its beauty that the Sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."
svHyLyte is offline   Reply With Quote
Old 19-02-2020, 12:52   #3
Registered User

Join Date: Sep 2012
Location: Now NZ after Med, Middle East, SE Asia, UK
Boat: Moody Carbineer 52
Posts: 102
Re: How can I back flush an engine (Perkins 4-236 in particular)?

Thanks for your reply and the info, svHyLyte; I appreciate the detail about the process. However, does this approach really move detritus which is down in the crevices of the block? Does Barnacle Buster work on rust in the block? (Not sure its avlbl outside US, but there are various equivalents.)
I have back-flushed non-marine engines and removed a LOT of rusty stuff in the past. My engines were flushed professionally a year ago, including having the heat exchangers removed, cleaned and refitted, followed by a 'forward' flush with a flushing agent and two 'rinses'. So the heat exchanger on the stbd engine should be very clean. The muck I see in my coolant is rusty red dust, so I don't think it comes from my heat exchanger (a lot of which is a non-ferrous alloy) but from the block. I was hoping to learn that the non-marine versions of these engines have a tap low down in the block, which in the marine versions would be replaced by a blanking bolt. That would enable me to really flush the block. But I haven't found out in reading various manuals etc if such a tap can be found in Perkind 4-236s.
keithw88 is offline   Reply With Quote
Old 19-02-2020, 15:56   #4
Registered User

Join Date: Sep 2012
Location: Now NZ after Med, Middle East, SE Asia, UK
Boat: Moody Carbineer 52
Posts: 102
Re: How can I back flush an engine (Perkins 4-236 in particular)?

I think I have confused two types of flushing! I want to flush the coolant side, rather than the sea-water side.
I have just re-joined Boat Diesel and found that non-marine engines do indeed have a cylinder block drain tap: and on inspection have found that on my marinised engine I see a bolt head in that location.
So my query now is can I get a tap and modify it to fit a fresh water hose and then can back-flush? (Bearing in mind svHyLte's point that shoreside water pressure can be pretty high!) I have emailed ASAP in the UK and await their response.
keithw88 is offline   Reply With Quote
Reply

Tags
engine, perkins

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Jabsco quiet flush flush button wireing Buehler45 Plumbing Systems and Fixtures 2 06-04-2016 06:58
For Sale: Perkins 4-236 Diesel Engine Capt Nemo Classifieds Archive 2 27-04-2015 21:50
For Sale: Perkins 4-236 Diesel Engine For Sale Capt Nemo Classifieds Archive 3 26-10-2013 13:09
Where to Find Perkins 4.236 Engine-Mounting Brackets Ben M-P Engines and Propulsion Systems 2 26-10-2011 14:39
Perkins 4-236 Engine Mounts sailorjg Engines and Propulsion Systems 1 11-05-2008 12:00

Advertise Here


All times are GMT -7. The time now is 01:44.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.