b&s blowing white smoke

Reply

  #1  
Old 11-20-08, 03:12 PM
Member
Thread Starter
Join Date: Jun 2006
Location: alabama
Posts: 101
b&s blowing white smoke

I have a yardmachine with a B&S 28T707 engine and a walbro LMT carb. It is running pretty good but every few minutes blows a puff of white smoke. It has an idle mixture screw and it is set at 1 1/4 turns out from seated. What adjustments should I make? Thanks for your help.
 
Sponsored Links
  #2  
Old 11-20-08, 03:23 PM
30yearTech's Avatar
Member
Join Date: Oct 2006
Location: Central Texas
Posts: 1,176
Gray, White or Bluish smoke pretty much indicates oil being burned in the engine. Check the oil level in the engine to make sure it's not overfull and if it is, check and see if the oil smells of gas. If gas has contaminated the oil, then in addition to needing an oil change, you most likely have a problem with the carburetor as well (but more then an adjustment will fix)
 
  #3  
Old 11-20-08, 04:48 PM
Member
Thread Starter
Join Date: Jun 2006
Location: alabama
Posts: 101
I checked the oil and it looks fine, level ok and does not smell like gas.
Could it be rings or something?
 
  #4  
Old 11-20-08, 05:49 PM
Member
Join Date: Nov 2008
Location: Moses Lake Washington
Posts: 6
In my experience, I would say it would most likley be valve seals. I have had lots of engines that do that and the rings are usually fine, the valve seals weap a little each time the valve is activated and the extra oil eventually runs into the cylinder. But don't quote me on that.
 
  #5  
Old 11-20-08, 09:31 PM
Member
Join Date: Oct 2005
Location: USA
Posts: 62
Originally Posted by smenguy View Post
I have a yardmachine with a B&S 28T707 engine and a walbro LMT carb. It is running pretty good but every few minutes blows a puff of white smoke. It has an idle mixture screw and it is set at 1 1/4 turns out from seated. What adjustments should I make? Thanks for your help.
How old (how many hours)? Based on my experience with a very similar B&S engine (28N707) Id bet you have a blown head gasket. Other than the smoke, my engine had been running fine and even checked out with a compression test (but ultimately failed a leak down test). Easy fix.

Some pix here of the head gasket repair here (although the engine eventually died due to other causes):
http://www.cardomain.com/ride/773108/2

Paul
 
  #6  
Old 11-21-08, 03:08 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,852
I agree on the head gasket. I've never seen valve seals cause any problems on a small engine.
 
Reply

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


Thread Tools
Search this Thread
Display Modes