Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 03-05-2015, 01:54   #31
Registered User

Join Date: Aug 2012
Posts: 811
Re: How does self bleeding work?

Self bleeding means I do it myself!
On my 2gm20 I use an outboard motor fuel line with a priming bulb before the lift pump. Squeeze the bulb to prime and bleed with the bleed screws. Much easier than using the lever on a manual pump. An electric pump might be even easier.

GrahamHO is offline   Reply With Quote
Old 04-05-2015, 20:35   #32
Registered User

Join Date: May 2014
Location: USA
Boat: 41' yawl
Posts: 462
Re: How does self bleeding work?

Originally Posted by Jd1 View Post
If you have air in the high pressure lines then your injectors will not fire. Air is compressible, diesel isn't - you can not build sufficient pressure to fire the injectors with air in the lines as the amount of diesel pumped by the injector pump is small. The pressure goes up a bit but the air compresses and acts as a cushion. The pressure can't get high enough to fire the injector.
Man this is difficult to explain considering how simple the concept really is!
As far as self bleeding, I can only speculate that the high pressure pump is fed by the electrical lift pump and will pump it's tiny volume as long as there is fuel on the pump input. The output pressure will be too low to fire the injectors but fuel flows through the fuel return system back into the tank which flushes air out of the system. Once sufficient air is removed the injectors fire.

I think we have a winner. Makes sense, thanks!

chris95040 is offline   Reply With Quote
Old 04-05-2015, 20:46   #33
Registered User
Stu Jackson's Avatar

Join Date: Jan 2011
Location: Cowichan Bay, BC (Maple Bay Marina)
Posts: 5,442
Re: How does self bleeding work?

Originally Posted by boeing1 View Post
pressing the preheat button should not start the electric fuel pump, it should come on when the key is on. preheat button should only heat the glow plugs, most engine require pressing both the glow plug and the start button to start the engine.
well that is how most of the boats I have worked operate.
Please be aware that many engines are wired to have the fuel pump ONLY run when the glow plugs are ON or the oil pressure is "made."

It requires a bypass to get the fuel pump to work when bleeding, and, IMHO, is a stupid way to wire the system, but that is what many folks have.

Mine is like yours on the fuel pump. We discussed it at great length on our C34 forum, since our Mark II boats with newer M35 engines came this way, while the older boats like mine, are simpler with an always-on fuel pump through the ignition switch, not the glow plugs.


However, on mine, the very LAST thing to do is to have to push BOTH the start and glow plugs at the same time. Makes NO sense. No reason to have both draw. I glow plug release then hit start. I installed a solenoid for the glow plugs, which come pre-installed on newer engines.

There are all sorts of different ways to do things, like it or not.

The trick is to learn what you have, how it works, and what to do with it.

Stu Jackson
Catalina 34 #224 (1986) C34IA Secretary
Cowichan Bay, BC, (Maple Bay Marina) SR/FK, M25, Rocna 10 (22#) (NZ model)
Stu Jackson is offline   Reply With Quote

Thread Tools
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
Do Self-Sealing Valve Couplings Work ? svpresent Plumbing Systems and Fixtures 3 24-10-2010 16:26
Bleeding Fresh Water System rjarrell Plumbing Systems and Fixtures 5 09-08-2008 04:24
Bleeding 4-108 jimisbell Engines and Propulsion Systems 21 24-05-2007 15:36
Bleeding keel seafox Construction, Maintenance & Refit 16 09-05-2007 21:06
Bleeding the fue lines on a Yanmar 3YM30 chesapeakesailor Engines and Propulsion Systems 10 18-09-2006 05:55

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 04:00.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.