Yanmar (3GM 20hp) Blue Smoke Problem - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 10-31-2001
Junior Member
 
Join Date: Oct 2001
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
animaashi is on a distinguished road
Yanmar (3GM 20hp) Blue Smoke Problem

I have a 1983 Irwin 34 with a Yanmar 3GM 20hp diesel. I have started noticing that at about 2000-2500 rpm''s I start to get blue smoke exhaust instead of clear. I don''t get it while operating with/without load under that rpm, or over 2600-3400.I just purchased a Yanmar shop manual and I''m more perplexed than ever. Could it be the breather tube assembly, and if so, why? Any suggestions? Thanks for the help!
Reply With Quote Share with Facebook
  #2  
Old 11-01-2001
Jeff_H's Avatar
Moderator
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,579
Thanks: 5
Thanked 95 Times in 71 Posts
Rep Power: 10
Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about
Yanmar (3GM 20hp) Blue Smoke Problem

I believe that blue smoke (vs white,black or grey) is lube oil burning. It is usually a sign of bad valve seals or piston rings. What perplexes me is that it only occurs at a certain range of RPMs.

Jeff
Reply With Quote Share with Facebook
  #3  
Old 11-01-2001
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,841
Thanks: 9
Thanked 75 Times in 68 Posts
Rep Power: 15
RichH will become famous soon enough
Yanmar (3GM 20hp) Blue Smoke Problem

Indications are possible compression ring problems. Suggest you do a compression test and an air pressure test of the combustion chambers.
Problem could be simply that the rings are sticking in their piston grooves. My 3QM30 used to do this and was solved by soaking the crankcase with "Marvel Mystery Oil" (super high detergent/solvent based oil - available at automotive speed shops) ..... running at NO LOAD until warm, let set a week, drain and replace with regular oil and 25% MMO thereafter - will help to keep the piston grooves and valve stems, etc clear of debris. Some mechanics use a mix of transmission oil and regular diesel grade oil for the same effect.
To check the breather tube, simply open the oil fill port and see if there is oil smoke coming OUT, if coming OUT - blocked breather; if suction IN - OK.
Reply With Quote Share with Facebook
  #4  
Old 11-05-2001
Junior Member
 
Join Date: Mar 2001
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
jfkal is on a distinguished road
Yanmar (3GM 20hp) Blue Smoke Problem

What to do if breather is blocked?
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Smokin'' Perkins cgha33 Gear & Maintenance 5 11-13-2003 09:19 AM
Yanmar engine startup smoke WillS Gear & Maintenance 4 08-23-2001 04:42 AM
Yanmar 2QM15 Problem shipley Gear & Maintenance 5 05-18-2001 09:17 PM


All times are GMT -4. The time now is 05:02 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.