Yanmar 3GM idles too high - SailNet Community
 
LinkBack Thread Tools
post #1 of 5 Old 08-15-2008 Thread Starter
Junior Member
 
Join Date: Aug 2008
Posts: 2
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Yanmar 3GM idles too high

I've just installed a new Yanmar 3GM30 and find that it runs very rough at anything less than 1100rpm. It runs smoothly over 1100rpm. "Rough" means that it seems as though it will vibrate off its mounts. Prior to starting the fuel pump and injectors were professionally serviced so for now I'm assuming there are no fuel issues. The installation book says the idle speed should be 850rpm. Any suggestions as to what I could try ?
gregjames is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 5 Old 08-15-2008
Senior Member
 
Join Date: May 2007
Posts: 551
Thanks: 3
Thanked 3 Times in 3 Posts
Rep Power: 9
 
The idle setting is a set screw on the throttle arm.

I would try reconsidering a problem with the fuel system. You have classic symptoms of an air leak. Start at the tank connections and check each one. Make sure your fuel filter is sealed well. Check all the bleed point bolts too see they have good crush washers and they are snug.
SteveInMD is offline  
Quote Quick Reply Share with Facebook
post #3 of 5 Old 08-15-2008
Senior Member
 
Join Date: Jun 2007
Posts: 536
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 9
 
Agree with Steve. Make sure you have enough fuel in the tank that the pickup tube is well under the level. Most tubes don't go to the bottom of the tank (they feed in from the top)
GBurton is offline  
Quote Quick Reply Share with Facebook
post #4 of 5 Old 08-15-2008
Senior Member
 
Join Date: May 2007
Posts: 551
Thanks: 3
Thanked 3 Times in 3 Posts
Rep Power: 9
 
If you open the final low pressure side bleed point (the one where the fuel enters the high pressure injection pump), and you activate the lift pump manually, do you get a clear strong flow of fuel, or is does it have any bubbles? Make sure you open the bolt until you can see the hole on the threaded part of the bolt. If you get any bubbles you have an air leak somewhere. Even if you don't I would still check over all connections. A small air leak can be hard to find when operating the lift pump by hand.
SteveInMD is offline  
Quote Quick Reply Share with Facebook
post #5 of 5 Old 08-16-2008 Thread Starter
Junior Member
 
Join Date: Aug 2008
Posts: 2
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Thanks all.
I revisited each connection, tightened it a little more, gave a couple of pumps on the manual pump lever to bleed at the fuel pump, and hit the start button. After a minute or so I tried to adjust the idle down and managed to get it running quite well at 900rpm. So it appears the problem is resolved and you correctly predicted an air leak.
Thanks again.
gregjames 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 3GM woes britcoal Gear & Maintenance 32 07-01-2008 02:24 PM
Starting Battery - Yanmar 3GM JohnRPollard Gear & Maintenance 14 03-11-2008 12:31 PM
Basic Thoughts on Tides Jim Sexton Seamanship Articles 0 11-17-2003 07:00 PM
Yanmar (3GM 20hp) Blue Smoke Problem animaashi Gear & Maintenance 3 11-05-2001 06:18 PM
Understanding High-Pressure Systems Michael Carr Seamanship Articles 0 04-06-2001 08:00 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