Diagnose your diesel engine - SailNet Community
LinkBack Thread Tools
post #1 of 3 Old 07-18-2008 Thread Starter
Senior Member
RickQuann's Avatar
Join Date: May 2005
Location: Leesburg, VA
Posts: 512
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
Diagnose your diesel engine

Received this in an email and thought that I would share it

Hints from Admiralty Yacht Sales -- Diagnose your diesel engine
While this is not intended to be an exhaustive list of methods to diagnose your diesel engine's general health, there are several non-technical techniques to check the health of your engine. Make sure your engine is warmed up before diagnosis.
Diagnose your diesel engine's running condition by the color of its exhaust:
Black smoke - Indicates unburned fuel/highly loaded condition
  • In situations where the boat has reached hull speed and the engine has enough power to try to make it go faster, black smoke will result. Back off the throttle a few hundred RPM's until the black smoke disappears or reduces to gray smoke.
Black smoke with oil sheen and soot on the water
  • May indicate plugged, worn or dirty injectors. Running the engine hard for 15 minutes or so may clean up the exhaust. If after this "blowing out" period the black smoke continues, injector service may be necessary.
Gray smoke
  • Indicates normal running condition. All diesels produce some level of gray smoke and may leave a sooty film on the transom of the boat. If a great deal of soot is present, see "black smoke".
White smoke
  • Probably indicates steam. Check engine temperature and volume of exhaust water to insure the engine is running at the proper temperature. In cold weather, white smoke is normal when engine is at operating temp.
RickQuann is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #2 of 3 Old 07-18-2008
Senior Member
Join Date: May 2008
Location: sw florida
Posts: 196
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
black soot in the water

I had this problem with a generator. The genset seemed to run just fine except that it looked like a tire fire in back of the boat and the water had an black soot over it. After two generator companies came out and checked the injectors and everything else you can think of they said we needed a new genset, this one was just wore out.(1750 hrs) After puting the thing back together again (2ND time) I just happened to check the air filter screen and it was completly closed with exhaust soot! So I cleaned the filter assembly and it was perfect! No smoke, no soot , just clean water out the exhaust. I guess you don't always get what you pay for. These guys weren't cheap. So I learned something new.The companies you hire don't always know more than you and make sure the filter screen is clean.
funsailthekeys is offline  
Quote Quick Reply Share with Facebook
post #3 of 3 Old 07-18-2008
Senior Member
trantor12020's Avatar
Join Date: Mar 2006
Location: Singapore
Posts: 702
Thanks: 4
Thanked 11 Times in 11 Posts
Rep Power: 12
hello funsailthekeys, I do think the genset company knows more than we think they know. its their business. what probably happen is this: send a service engineer and he sell spare parts, send a sales engineer there and he sells a whole new genset. so I guess it make prefect cents to send a sales engineer.

2002 Hunter 326, SV Millennium 2
1999 Macgregor 26X, SV Millennium
trantor12020 is offline  
Quote Quick Reply Share with Facebook

Quick Reply

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


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

Email Address:


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
Runaway Diesel Engine Ben Hilke Gear and Maintenance Articles 0 07-19-2004 08:00 PM
Surveying a Diesel Engine Tom Wood Buying a Boat Articles 0 01-26-2003 07:00 PM
Surveying a Diesel Engine Tom Wood Gear and Maintenance Articles 0 01-26-2003 07:00 PM
Diesel Maintenance Mark Matthews Gear and Maintenance Articles 0 06-10-2002 08:00 PM
Replacing the Diesel Engine Sue & Larry Gear and Maintenance Articles 0 06-12-2000 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