LT1000 Lawn Tractor - surging

   / LT1000 Lawn Tractor - surging #1  
Klipper

Klipper

Member
Joined
Mar 8, 2018
Messages
47
Location
TX
Tractor
2018 Kioti CK2510
No matter what I do I can't seem to get my old LT1000 to run smoothly.

I've watched (and followed) a ton of the Taryl Fixers All videos, and have adjusted the governor, valves, carb (even installed a new carb) and the darn thing just keep surging. I can literally watch the governor go up>down>up>down.... :mad:

Any ideas?
 
   / LT1000 Lawn Tractor - surging #2  
Does the carb have a high speed adjustment ?

Does it surge at idle speed and also at high speed ?

Richard
 
   / LT1000 Lawn Tractor - surging #3  
" I can literally watch the governor go up>down>up>down...." That's part of the pulse mulching system... Briggs /Nikki carb or?
 
   / LT1000 Lawn Tractor - surging
  • Thread Starter
#4  
It had the stock carb (I guess a Nikki) and I replaced it with an Amazon special - (probably didn't even need a new carb, but I wanted to see if it might be the culprit), but adjusting the high speed adjustment had little effect with either carb. It was kinda weird. But I did adjust as best I could. And there are not air leaks on the intake side. It surges at all speeds but way more noticeable at high speed.
 
   / LT1000 Lawn Tractor - surging #5  
Klipper said:
It had the stock carb (I guess a Nikki) and I replaced it with an Amazon special .
Click to expand...
You guess? Well are you wanting us to just guess at your problem because that's all we can do without at least knowing A. What kind of carb was and what kind is now on there B. Kohler or B&S engine (preferably including model #) C. If you made sure flow isn't restricted from tank to carb D. If you tested for water in fuel E. When and how it began surging D. As much other history as possible on what has been done to engine. Until then my guess is it needed a carb and you mis-assembled and/or mis-adjusted governor which is easy to do and a bear to straighten out once out of wack.
 
   / LT1000 Lawn Tractor - surging
  • Thread Starter
#6  
Yes - I guess. My mower is older (model 917.276390) and the online parts fiche don't even show the carb anymore. I bought a Carbhub carb off Amazon for the Craftsman 18hp LT1000 and it was the same. Just to see if that would do it. And as I said, I followed the instructions on more than one Youtube vid to adjust the governor, which seemed pretty straightforward.

There is no water in the gas. The fuel line is new and flows well. When it began was a long time ago and I just recently got the nerve up to try and deal with it myself.


carb.png
 
   / LT1000 Lawn Tractor - surging #7  
So the main cause of a surge on these is the idle air bleed being partially plugged. The original carb you show is a Walbro, typically replaced by a Nikki. AM carbs for these are not reliable . Yours is probably an LMT. https://outdoorpowerinfo.com/repairs/#id_nikki See views 13 and 14 under the LMT
 
   / LT1000 Lawn Tractor - surging #9  
The exellent resource tomplum furnished is superiour to what most (certainly me) can offer.
Accross the board for several years I've found idle jets on all carbs are on the verge of being restrictive and the slightest thing pushes it over the brink of performance. Jet size is held to the very minimum to help meet emissions standards. I use welding torch tip cleaners on idle jet of every carb i clean. Fair warning,it's easy to ruin the jet if cleaner isn't held perfectly straight. In 90% of cases I've found that slightly increasing jet diameter help's performance but simple removing oxidation film which solvent cleaner doesn't cut is an improvement. Above 800-1,000 cc engine carbs require drill bits to make neccessary alteration. Truth is small engine carbs have become near impossible to maintain and as tomplum said aftermarkets are worst of all.
 
   / LT1000 Lawn Tractor - surging #10  
jaxs said:
The exellent resource tomplum furnished is superiour to what most (certainly me) can offer.
Accross the board for several years I've found idle jets on all carbs are on the verge of being restrictive and the slightest thing pushes it over the brink of performance. Jet size is held to the very minimum to help meet emissions standards. I use welding torch tip cleaners on idle jet of every carb i clean. Fair warning,it's easy to ruin the jet if cleaner isn't held perfectly straight. In 90% of cases I've found that slightly increasing jet diameter help's performance but simple removing oxidation film which solvent cleaner doesn't cut is an improvement. Above 800-1,000 cc engine carbs require drill bits to make neccessary alteration. Truth is small engine carbs have become near impossible to maintain and as tomplum said aftermarkets are worst of all.
Click to expand...
I would guess that you have hit the nail on the head. On several occasions I have had to use a small nail or hand held drill to open non-adjustable main jets. You do have to be careful not to make it too big. You may have to do several adjustments to get rid of the surging.

High engine speed fuel mixture is mainly controlled by the main jet, idle mixture on the other hand is mostly from the idle jet.

Richard
 
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