Another B&S Intek white smoke problem

Reply

  #1  
Old 07-07-15, 03:40 PM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
Another B&S Intek white smoke problem

Have spent a lot of time reading through all the other threads where white smoke was the main symptom of this engine. Thanks to all that have helped others with the various issues that cause this. Here is what I'm dealing with.

I inherited riding lawn mower with a 17.5 HP B&S Intek Model 31g777 0290e1 that was running fine earlier this season but the last time I went to mow it would fire up for a few seconds then started puffing white smoke before the engine died. Upon closer examination there has definitely been oil coming out of the valve cover and/or exhaust pipe.

I have done the following maintenance in an effort to fix the problem:

New fuel filter
New air filter & foam prefilter (old air filter did not have any oil on it)
New spark plug (old spark plug was oiled)
Drained oil (which definitely had gas mixed in it)
Filled oil to proper level

Found the delicate governor spring was broken so replaced it.
Replaced head gasket (old gasket did not appear to be broken anywhere)
Adjusted valves (exhaust valve was a bit tight)

When I put it all back together the engine fired up just fine but was still blowing white smoke out of the exhaust. I shut it down after letting it run for about 1 seconds as it appeared to be getting worse (more smoke). Is there a chance I need to let it run a bit longer to burn out any remaining oil? Didn't want to do so if it was going to cause more damage.

If there is still something causing the issue then reading other posts around the web with similar symptoms it sounds like it could still be:

Crankcase breather valve
Float needle
Bad rings

Any other thoughts? Thanks in advance for the help!
 
Sponsored Links
  #2  
Old 07-07-15, 03:44 PM
Member
Join Date: Jan 2011
Location: USA
Posts: 4,185
I'd start with rebuilding the carb.
 
  #3  
Old 07-07-15, 03:57 PM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
That is where I was headed next but thought I'd post the entire story in case I was missing something.

I purchased the float needle, seat & bowl gasket today while I was out running errands. Any other parts of the carb I should be looking at while I have it torn apart?
 
  #4  
Old 07-08-15, 05:04 AM
Member
Join Date: Jan 2011
Location: USA
Posts: 4,185
Did you pick up some carberator cleaner?
 
  #5  
Old 07-08-15, 05:24 AM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
Yes - although just the spray type. Not the gallon can carb dip type. This will be the first time I've done any type of carb rebuild so I'm open to tips of what to focus on above and beyond the float needle/seat.
 
  #6  
Old 07-08-15, 06:39 AM
Member
Join Date: Dec 2006
Location: Canada
Posts: 528
I would get a new valve cover gasket if you suspect a leak. I would think that you would see it but if oil is dropping on to that hot exhaust pipe, it is going to smoke for sure. Also, keep in mind that if the smoke is coming from oil getting into the inside or outside of the exhaust pipe, it can smoke for a while after the problem is resolved, before it eventually clears up.

Also, if you have gas in the oil, it is coming from a leak in the carburetor's inlet needle. A rebuild is a good idea and a better one in addition is a $7 manual fuel shut off valve installed between the gas tank and the fuel filter. Shut it off when stored and turn it on 15 seconds before you start it up and you will not have anymore gas in the oil.
 
  #7  
Old 07-08-15, 06:44 AM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
Thanks Optsy! I need to put a concrete block on the seat so the engine doesn't cut out and take a closer look up front when it is running to see if a valve cover gasket leak is dropping oil on the exhaust. Makes sense.

It appeared that gasket is RTV'd to the cover - do you just carefully scrape it off before putting the new one on?

Definitely doing the float needle and have seen a fuel shut off added in some of the YouTube videos so that is an easy fix as well.

Will report back after the next round of repairs - thanks all!
 
  #8  
Old 07-08-15, 09:14 AM
Member
Join Date: Dec 2006
Location: Canada
Posts: 528
Yeah, just scrape it off and you really do not need any RTV if you have a proper gasket for the valve cover.

Also, you should be able to run the motor without sitting on the seat as long as the safety brake is on and the blade is not engaged. In any event if a concrete block works, no harm done.
 
  #9  
Old 07-08-15, 09:44 AM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,821
The only way the carburetor could be causing this is if it is leaking sgas into the oil. If it is, you will be able to pull the dipstick and see the oil level over-full and smell gas in it. If that's not the case, then the carb isn't the problem.

I suspect oil dripping on the exhaust or bad rings.
 
  #10  
Old 07-08-15, 10:12 AM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
There was definitely gas in the oil so I'm focused on the carb at the moment. Will keep you guys posted!
 
  #11  
Old 07-08-15, 12:42 PM
Member
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,729
In terms of the oil in the exhaust, given the source was fixed, you will need to run the engine for some time to burn out all the oil in muffler and pipe. A few seconds of run time won't do it.
 
  #12  
Old 07-10-15, 11:53 AM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
marbobj - thanks for confirming that. I figured that was the case but didn't want to risk it.

Replaced the float needle, ran a Qtip around inside the float needle seat and had to also replace the float bowl gasket and the sealing washer between the float bowl and the solenoid. Added an inline fuel shut off valve as well.

Started it up and let it run for a couple of minutes - the white smoke wasn't nearly as thick as it was last time starting out and continued to thin out as the engine ran. Shut it off and had a bit of smoke coming from the muffler "box" that the exhaust runs into but am guessing I'll have that for awhile unless I take it off and clean it out.

Has been raining here for days but tomorrow appears to be a dry day so I'll do a longer run of the engine while I'm cutting the yard and see if we can close the chapter on this repair!
 
  #13  
Old 07-10-15, 03:15 PM
Member
Thread Starter
Join Date: Jul 2015
Posts: 7
Sun came out unexpectedly this afternoon and I couldn't wait. Seems to be running good as new - mowed for over an hour and all went well. Now I need to go bale the hay I have spread all over my backyard...

Thanks all!
 
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