Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Sign in to follow this  
Kenh

low speed stumble

Recommended Posts

Kenh
When my 7116H is at idle or slightly above it will sometimes "stumble" for a few seconds then run fine again. Sometimes you think it will die completly! I've adjusted the idle mix and also the high speed. The engine runs fine at anything over 1/2 to 2/3 throttle. It has very good power and pulls fine under heavy or light load. The carb is about five years old (bought new) to replace the old worn out carb. Fresh gas, good spark, need to add oil after about 4 hours run time. No trash in the cooling fins. It's not a big problem. I just know it shouldn't do this and am at a loss for a fix. Thanks in advance for the help!!! Ken

Share this post


Link to post
Share on other sites
rsnik
I have a '96 Murray with 48 inch deck and 18.5 vertical Briggs twin. The tractor got demoted to brush hog because the 7013S mows the large lawn areas in half the time, puts a much nicer finish on the lawn, is much more comfortable, more maneuverable and uses half the gas (18.5 Briggs is thirsty). I mow down the weeds, brambles and brush on the wild side of the property with the Murray because the sandy ground, I'm not kidding, grows rocks. The dirt is glacial sediment and these fist sized, round rocks come to the surface and you can't see them in the weeds. The Murray was doing just what you described last night and then ran out of gas. I added Sea Foam to the gas when I refilled. I mowed down brambles and weeds for another 45 minutes at WOT. When I was done and the mower was idling outside the shed I noticed the stumble was gone. Carbs have a main jet circuit and an idle jet circuit. I think maybe the tiny, idle jet circuit may get clogged with sediment or whatever and the Sea Foam cleans it out.

Share this post


Link to post
Share on other sites
BLT
It could be a balance between low speed jet and governed throttle where it is loping and lopes far enough to die out. I have the same problem but when it warms up, it mellows out most of the time.

Share this post


Link to post
Share on other sites
Kenh
Mine is better when it is "cold". At first start it idles just fine. There is no lope from the governor. It just plain acts like the key was shut off for a second or less. Could the governor be sticking a bit? Governor works fine at high speed, but could it have a sticky spot at low speed where the governor weights don’t have enough force to overcome the sticky spot????? I also wonder if there might be a slight amount of vapor lock going on. I've adjusted the high speed mix as rich as possiable to help with any cooling issue and every setting leaner than that. Same story with the low speed mix. I will check the points and condenser, even though they are only about 1 1/2 years old. Maybe I need to re-power with a turbine:D or not. Hey ya gota have dreams!!!

Share this post


Link to post
Share on other sites
rsnik
You have the kill wire which runs from the ignition switch to the magneto and the points wire which runs from the magneto coil to the points box. If either wire has a bare spot anywhere and grounds momentarily the effect would be just like you switched off the ignition switch for a second.

Share this post


Link to post
Share on other sites
DMedal
Ken- I'm not real sure whether you're talking about operation at idle or slightly above. In other words, does the governer enter into the picture? With the throttle all the way to "slow" it should, ideally, idle - without the governor engaging. The throttle should be all the way over on the idle speed screw and stay there. See if the problem goes away if you put a finger on the throttle at the carb and keep the governor from pulling it open. If so it is the loping that is a problem and you may not get steady performance at 1/8th throttle. Open that sucker UP! On the other hand if it is truly on idle you should ideally be able to tweak speed and mixture to get it to purrrrr. Let us know?

Share this post


Link to post
Share on other sites
rsnik
Hi Duckman, If governor adjustment is causing loping at idle on Kenh's Briggs 16, what is the procedure to adjust the governor so that you don't have to press your finger on the idle screw to get the idle down?

Share this post


Link to post
Share on other sites
DMedal
adjust throttle linkage from the control so it isn't pulling it up slightly, and adjust the little set screw on the carb throttle shaft to increase the idle speed so it can run steady on idle without a little extra on the knob. The finger on it was a diagnostic step... is the engine stumbling because the governer is trying to open the throttle or is the governer trying to open the throttle because the engine is about to stall? If the later and you hold the throttle on idle it will die. If the former it will run happy and fine. That's how mine runs anyway. -Don

Share this post


Link to post
Share on other sites
MrSteele
Sea Foam is not easy to come by in the Sunny south, at least not in North Alabama where I live. I have found that an occasional 1/2 cup or so of motor oil in the gas tank does about the same, sometimes I use Marvel Mystery oil for the additive. Even a small amount of fuel injector/carb cleaner for the gas tank of automobiles has a tendency to keep the fuel system/valve chamber/combustion chamber clean and carbon free. I always add a bit of oil after the fuel additive tank. Not certain why, I just do it. I rarely have many of the problems I see here with fuel systems. I saw in another thread that one should have several Simplicitys to use, simply because one or the other would always have some sort of running problem. I can't understand all I know about such situations. I have 2 cast iron Briggs engines, an I/C and three smaller engines on toys. I started a Yazoo last week that had not run in over two years. It is a recoil start, and started on the second pull, just as it always has. Even the old ZZ starts on the first pull if you hold the choke shut. Your problem sounds like a bare wire somewhere. I'm not sure of what the engine is in your tractor, but if it is a cast iron Briggs, check the points/condensor cover. Mine was shorting out where the wire passed through the cover. Silicone straightened that out.

Share this post


Link to post
Share on other sites
Kenh
Great tips guys!!! I'm in the middle of a house remodel, so when I have time I'll look at those problem areas. I kind of am leaning in the direction of the governor adjustment as I had the motor out when I converted it back to the stock ignition. Had most of that apart repairing what the previous owner had screwed up. I guess I should have posted that info in my first post. (DUH) The only other thing I can think of is the previous owner left the carb bolts loose. While I was tilling up my yard for new grass it ran with the carb dangling so loose that it would not restart after I shut it off. It had no gaskets at the head!! Don't know how much dirt it sucked through the motor. Seems to run fine except for this little hick-up. Right now all I have is bare studs,no insulation or sheet rock, no wire in the house, half finished plumbing and heating system and we want to try to move in before 2008. The tractor runs good enough that I'm not going to putz with it right now. It's been running like this for two or three years now. I'll make note of these tips and take a look when I have time. Thanks!!!!!:D

Share this post


Link to post
Share on other sites
rsnik
Hi MrSteele, I probably made the comment about having all kinds of tractors and here is how it works. You have running tractors, non-running tractors and parts tractors. Running tractors are used for mowing the lawn, snow removal, landscaping or working the garden. Some owners favor having a tractor dedicated to each application. Next you have non-running tractors, typically recently acquired, sometimes called "winter project" tractors. If you scab parts off this class of tractor it is officially borrowing the parts since you are eventually going to return the tractor to full operating status. Then you have parts tractors which you purchased because the tractor has an engine or axle tube you need or you want it as a general store of spare parts. You may freely scab parts off a parts tractor since there is no expectation of the tractor ever returning to service. A tractor can develope multiple issues, for example internally caused rising, no load idle and smoking or knocking plus the "magic smoke" comes out of the regulator and the axle tube breaks. This may cause you to park the tractor in the back of the shed until you find a parts tractor with a good engine, regulator and axle tube for $90, since spending $600 in dealer/eBay parts to fix the problems will empty the cookie jar and you will have no tractor dough when that one owner, new condition, 3112H Sovereign with power lift shows up for $550 that you have to buy for cash right now or lose it forever to another buyer and you will never find another one that good, LOL! Wow! Talk about life imitates art! My 717 has the above described engine problems and has been waiting for over a year for an engine transplant. I just now won this tractor on eBay for $89 that has a good engine I am going to put in the 717 and put her back in service. Woo Hoo!


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)

    • B10Dave
    • Rfp55
    • Skelsey1989
    • rockfangd
    • MARK (LI)
    • SmilinSam
    • Mach1martysr
    • kwt
  • Today's Birthdays

    1. Andust
      Andust
    2. Noly
      Noly
      (69 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
       
      · 8 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

×