Yanmar yms12 wont idle - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 19 Old 05-15-2012 Thread Starter
s/v Ubiquitous
 
Domknotty's Avatar
 
Join Date: May 2011
Location: On the hook in Destin Florida Harbour
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
 
Send a message via Yahoo to Domknotty
Yanmar yms12 wont idle

Help, I just refurbished (cleaned like new) the fuel tank, replaced the filters, bench tested the fuel pump...works. No leaks that I can detect. Cranks like a jem at 1/4 throttle, to keep it running I have to rev it a little and can back it to 1/4 - 1/2 throttle and will purr but any lower it chokes out. Checked to make sure choke is open but still wont idle. ideas?

Bill Brown
Pensacola Florida
1972 Morgan 35
The good ship Ubiquitous
Blog Addy
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Domknotty is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 19 Old 05-15-2012
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 2,891
Thanks: 2
Thanked 76 Times in 70 Posts
Rep Power: 9
 
Re: Yanmar yms12 wont idle

At what RPM does it stall? There is an adjustment on the throttle linkage of most diesels to set the idle speed. Note that diesels don't have a choke.
JimsCAL is offline  
Quote Quick Reply Share with Facebook
post #3 of 19 Old 05-15-2012 Thread Starter
s/v Ubiquitous
 
Domknotty's Avatar
 
Join Date: May 2011
Location: On the hook in Destin Florida Harbour
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
 
Send a message via Yahoo to Domknotty
Re: Yanmar yms12 wont idle

I have no rpm gauge but if a idling motor runs at 600rpm and full throttle is around 3500 I would say it chokes out (for lack of better words) at about 1000-1200 rpm, ALMOST slow but above idle. If I catch it I can give full throttle and keep it running, if im late it dies with a chug.

Bill Brown
Pensacola Florida
1972 Morgan 35
The good ship Ubiquitous
Blog Addy
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Domknotty is offline  
Quote Quick Reply Share with Facebook
post #4 of 19 Old 05-15-2012
Member
 
Join Date: Sep 2008
Location: Vancouver, BC
Posts: 68
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 7
 
that's not a choke

Make sure the fuel shut off is not engaged and the cable moves freely. Sounds like it is not getting enough fuel.
KBuckley is offline  
Quote Quick Reply Share with Facebook
post #5 of 19 Old 05-16-2012
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 2,891
Thanks: 2
Thanked 76 Times in 70 Posts
Rep Power: 9
 
Re: Yanmar yms12 wont idle

Does sound like the fuel is getting cut off early if it indeed won't run below 1000-1200 RPM. Is your engine stop a separate control or engaged by moving the throttle past idle? If the the latter, it could just be a simple adjustment or a sticking cable like KBuckley suggests.
JimsCAL is offline  
Quote Quick Reply Share with Facebook
post #6 of 19 Old 05-16-2012 Thread Starter
s/v Ubiquitous
 
Domknotty's Avatar
 
Join Date: May 2011
Location: On the hook in Destin Florida Harbour
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
 
Send a message via Yahoo to Domknotty
Re: Yanmar yms12 wont idle

due to a broken choke cable I am hopping from cabin to cockpit to adjust the choke and hit the engine kill lever.

Could it be my fuel pump, when I took it off I bench tested it and got a good flow by pumping the lever with no sign of leakage.

Another note, before cleaning the fuel tank it did idel, like a charm actually, but did not like going into higher rpm's. Maybe this will help.

Bill Brown
Pensacola Florida
1972 Morgan 35
The good ship Ubiquitous
Blog Addy
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Domknotty is offline  
Quote Quick Reply Share with Facebook
post #7 of 19 Old 05-16-2012 Thread Starter
s/v Ubiquitous
 
Domknotty's Avatar
 
Join Date: May 2011
Location: On the hook in Destin Florida Harbour
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 5
 
Send a message via Yahoo to Domknotty
Re: Yanmar yms12 wont idle

also, if I put an electric fuel pump inline before the fuel filters, would it blow the diaphragm out of the manual fuel pump or should I bypass the manual fuel pump all together? Just an idea, I would really rather fix it then throw money at it.

Bill Brown
Pensacola Florida
1972 Morgan 35
The good ship Ubiquitous
Blog Addy
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Domknotty is offline  
Quote Quick Reply Share with Facebook
post #8 of 19 Old 05-16-2012
Over Hill Sailing Club
 
smurphny's Avatar
 
Join Date: Feb 2009
Location: Adirondacks NY
Posts: 3,568
Thanks: 89
Thanked 107 Times in 104 Posts
Rep Power: 7
 
Re: Yanmar yms12 wont idle

A diesel with a choke? Did you find all the air bleeders? Sometimes they are not easy to find. Bleed the injectors right at the banjo fittings if all else fails.

Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.
smurphny is offline  
Quote Quick Reply Share with Facebook
post #9 of 19 Old 05-16-2012
Senior Member
 
dabnis's Avatar
 
Join Date: Jul 2007
Location: Truckee, CA
Posts: 8,677
Thanks: 2
Thanked 116 Times in 114 Posts
Rep Power: 9
 
Re: Yanmar yms12 wont idle

Quote:
Originally Posted by Domknotty View Post
due to a broken choke cable I am hopping from cabin to cockpit to adjust the choke and hit the engine kill lever.

Could it be my fuel pump, when I took it off I bench tested it and got a good flow by pumping the lever with no sign of leakage.

Another note, before cleaning the fuel tank it did idel, like a charm actually, but did not like going into higher rpm's. Maybe this will help.
If it didn't pull max RPM's under load before could be dirty or over pitched prop? Maybe a clogged vent? or fuel pickup tube screen in the tank? No idle after cleaning, maybe some debris broken loose and partially blocking passages somewhere? could be hard to find. Air leak somewhere? A pressure pump would probably show where:


The Diesel Page, Electric Lift Pump and Racor Filter installation

Try disconnecting all the control cables and manually open throttle
Check all connections, make sure there is no air spaces in filters.
You could by-pass the tank with a seperate fuel source?
It appears that something happened after you cleaned the tank?
If all else fails you might take the pump/governor assembly to a shop for cleaning and re-calibrating. If so make a mark on the block and pump housing for easy re-install. Let us know what you find.

Paul T
dabnis is offline  
Quote Quick Reply Share with Facebook
post #10 of 19 Old 05-16-2012
Member
 
Join Date: Sep 2008
Location: Vancouver, BC
Posts: 68
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 7
 
Re: Yanmar yms12 wont idle

Please describe what you are calling the "choke". There should not be a choke on a diesel....

Thanks
KBuckley is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 2QM15 Overheating at Idle... backcreeksailor Gear & Maintenance 35 08-16-2012 10:58 AM
Yanmar SB 12 wont reach maximum RPM in neutral weststar Diesel 8 02-28-2010 06:22 PM
yanmar yse 8hp wont start warm andersj81 Diesel 9 07-30-2009 06:42 PM
Yanmar Idle doesn't return to low stop ereiss Gear & Maintenance 3 06-02-2009 05:20 PM
yanmar wont start((winterized)) codmander Gear & Maintenance 17 04-16-2009 07:14 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome