Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Sign in to follow this  
tej

B112 running rough

Recommended Posts

tej
Well I finally got the carburetor rebuilt on my B112. I adjusted the carburetor per the Briggs manual. Tractor was running nice and smooth until I'd used it with the loader for about 15 minutes. Then it sounded like the gas was pre-igniting and the engine started to get hot. Seems almost like the timing is advanced too much. This is the engine that was pumping raw gas out the exhaust when I tried to start it several weeks ago. Besides rebuilding the carburetor I drained and change the oil, removed the head and cleaned out the carbon, oiled the piston and moved it up and down to coat the cylinder walls and then wiped out the excess oil, also replaced the spark plug. Any ideas on what's making the engine run this why? Tim

Share this post


Link to post
Share on other sites
StanS
If it only does it hot you may have to put a shield between the carb and muffler. We had a problem with this 3 or 4 years ago the gas would boil in the float bowl and flood the engine out. Around here it seems the gas changed, and we don't see it now much. Briggs told us how to address this problem back then,and said it was spotty around the country and seemed to be due to gas blending. If you are using gasahol the problem may be agravated.as it is worse for this. If it is detonation (ping) it may be due to some little point or edge in the chamber that glows and preignites. Since you have cleaned the carbon (the most common culprit) out, should be OK. May be just poor gas might try a different brand, also double check point setting as this changes the timing. Don't know if this will help, but its free, so take it for what is worth. Good luck, AL

P.S. Those Briggs carbs are prone to float bowl leaks where the emulsion tube seats in the float bowl Inlet needle and seat will pressure ck ok but carb will leak. If this happens take an old tube (Main Jet) grind the threads off and put a little FINE valve grinding compound on the surfaces where it seats in the flaot bowl lap it in and put a little teflon washer on the seat part. I'll post a part # to get this washer. They gave it to us in Brs school its for something else and I've forgotten what, but I'll get it.

Share this post


Link to post
Share on other sites
Kent
Another thing might be the exhaust valve is starting to hang up in the guide from deposits on the stem - if this is the case you will need to remove it for cleaning. If the valve is worn it is time for resurfacing both valve and seat.

391413 is the B&S part number Al is talking about for the teflon washer thats to be used if it is still leaking fuel - just disgard the little pin that comes with it. I tried it once but without success :(

Share this post


Link to post
Share on other sites
tej
Al, Thanks for the information. When I bought the tractor it had a upright muffler mounted on it. This came out of the engine about 5" to a 90 degree elbow and up about 5" to the muffler. When working on the tractor I also replaced the exhaust system. I brought it out 3" to two 45 elbows and up 4" to the new muffler. I put a 6" stack on top of the muffler. The old muffler was rusted out with many holes probably causing very little back press or heat. The new muffler is probably causing back pressure and heating up the exhaust pipe. This could in turn be heating the carburetor and boiling the fuel. The muffler, although not OEM for AC, is a Briggs muffler designed to be used with that type of engine. I will try the heat shield between the carburetor and the exhaust. Does Briggs sell a heat shield for this purpose or does one have to fabricate it. The gas I'm using runs fine in the B12. Tim

Share this post


Link to post
Share on other sites
Guest
Where do I get my hands on a heat shield? My B-1 has
had the problem of cutting out when it gets hot for
years. It acts like it is running out of gas when the
cutting-out starts. I've tried several things without
success over the years. A heat shield may be the cure.
Thanks,
Roy

Share this post


Link to post
Share on other sites
B-Man
I have a Simplicity 4212 with B&S engine that does the same exact thing. I rebuilt the carburetor and installed a new throttle shaft as the old one was worn out, but problem still exists. Runs for about 15 minutes then acts like it is starving for gas. If I apply the choke fully, it will start back up and run enough to get it back to the garage. Let it cool for 10 minutes and it will run for another 15 minutes before it starts surging again. Seems to cutout with a sort of rhythm....very annoying at best.

Share this post


Link to post
Share on other sites
Kent
After reading all the above messages and having the pleasure of owning an old Landlord 2010 ,for 11 yeras I would like to put in my 2 cents....
First Bruce (I believe) you had carb problems to begin with ,you rebuilt the carb and other things ,but the problem still persist ,from what I have
read in your note you have a sticky float or a float with a leak (did you shake the float looking for H2O ? )you have altered or changed the problem
but I think it is still in the carb.....
Second my lanlords gas tank is a sponge for H2O, I have a fuel filter at the low spot of my fuel line to the carb ,at least every other month I disassemle
the line and drain the H2O from the line and every fall I flush the tank to get rid of the water....
Last the heat shield that goes around the muffler is there to (WARM/HEAT )the carb in the winter months ....try running without it and your governor assembly freezes up
from all the snow being sucked in by the flywheel ,I know this because I live in Vermont...
Good luck Jim :)

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

  • Who's Online (See full list)

    • mike_sdak
    • thom
    • smalljob
    • tadams
  • Today's Birthdays

    1. Mustangsvo
      Mustangsvo
      (37 years old)
    2. RenegadeJ
      RenegadeJ
      (82 years old)
    3. srwven
      srwven
      (50 years old)
  • Recent Status Updates

    • Paul M.Murphy

      Paul M.Murphy

      Hello glad I got on this site. I hope to upload a couple of photos of my Simplicity Broadmoor 
      Model 707 Tractor. I have replaced all the belts on it and installed a new ignition switch.
      Have a mower deck which was in poor shape , repaced a couple of bushings and welded the
      deck where there was some holes. The tractor and mower deck came from a friend and the 
      mower deck metal was getting pretty thin. Some new metal was put in it and we also undercoated the underside of the deck. This was done by my friend Greg Toulman.
      I have not put the mower deck on the tractor yet, waiting for Greg to come home and give me a hand. Can you please tell me if there is a manual for the mower deck and where I could get one.
      I would also like to get some moon wheel discs as well.
      I will try and down load some photos of the tractor when my wife shows me how to. 
      I really love driving this tractor and also how well it is made compare today's tractors, especially the flexible rear end and the rollers.
      Tell the next time 
      Paul
       
      · 9 replies
    • jbrooks

      jbrooks  »  Talntedmrgreen

      Josh
       
      folowing  this from a link at the downloads.  I just rescued an AC 920 with the lambodini diesel. I can' t download  yet .  Where did you find the PDF copy you posted. . I would like to figure out how to adjust the injection pump. 
      I assume it's a bosche, correct
      · 0 replies
  • Adverts

×