JD LT133

dtrain911 · Jun 5, 2022

Inherited this tractor with a home purchase last year. Seems to be about 20 years old from some of the paperwork I found. Once we took ownership, I went ahead and completed the following:
- oil/filter change
- new belts
- fuel filter
- air filter

Ran fine until this year. I was out mowing and it started smoking from the front end. When I checked it out, I found gas was going down into the muffler so I replaced the carburetor with a knockoff since the JD version is $225. This stopped the gas from pouring into the muffler but the tractor won't run smoothly. Low speed isn't too bad but by the time the lever gets halfway up, it will start surging. No change when riding it around or putting it under load with the blades running. I checked the fuel filter and the gas inside seemed low. I went ahead and changed it as well as the fuel pump but no change. It seemed to smooth out a little bit if I ran it and pushed the lever partially into the choke so I figured it still might be the carburetor and the knockoff I bought wasn't cutting it so I got the JD version and still no change.

Any thoughts would be appreciated.

tomplum · Jun 6, 2022

For a test, drop a piece of fuel line into a gas can and hook to the pump and see how it runs with the donor can. If your lines are getting spongy or plugging, the pick up tube in the tank cracked or plugging or the vent in the fuel cap is plugged- it should run up good.

tomplum · Jun 6, 2022

Welcome to TBN

dtrain911 · Jun 6, 2022

tomplum said:
For a test, drop a piece of fuel line into a gas can and hook to the pump and see how it runs with the donor can. If your lines are getting spongy or plugging, the pick up tube in the tank cracked or plugging or the vent in the fuel cap is plugged- it should run up good.

Tried it and it seems to be fine. I checked the cap to see if it was vented and it looks good. Thanks for the suggestion

dtrain911 · Jun 7, 2022

Here's an update: checked the gap on the ignition coil and adjusted it to .010 which seemed to even out the higher idle so now it's good at low and high but surging in the middle. I feel like the problem is in the governor linkage. I can't find a picture of what it should look like to compare with my own. If anyone has a pic or a link to something similar I would appreciate it. I can find the exploded diagram on parts websites but it doesn't really help.

Richard001 · Jun 7, 2022

Yep, sounds like the engine is searching for the right speed (rpm). Are there both low and high speed adjustment's jets on the carb ?

If so, set the low speed a little richer.

tomplum · Jun 7, 2022

So when you did the donor can, everything was normal?

dtrain911 · Jun 8, 2022

Richard001 said:
Yep, sounds like the engine is searching for the right speed (rpm). Are there both low and high speed adjustment's jets on the carb ?

If so, set the low speed a little richer.

Unfortunately it doesn’t have any adjustments and this is the new walbro from John Deere