LT133 13 HP engine, gas leaking into the oil

   / LT133 13 HP engine, gas leaking into the oil #1  

FTG-05

Elite Member
Joined
Jan 7, 2011
Messages
2,588
Location
TN
Tractor
Kubota L4330 GST w/FEL, Kubota RTV-XG850, Kubota ZD326S
I have the JF LT133 lawn tractor and the oil started leaking out of it, after +10 years of never leaking a drop. Checked the oil level and it was way high! I thought maybe my son had overfilled it, but asked him and he said no. I drained some of it out and it came out real runny and smelled of gas.

This happened about 12 years or so ago just after I bought the tractor and JD fixed it under warranty. Well, its out of warranty now, so I need to fix it myself if I can, cause I don't want to pay the JD bill.

Ideas on what is happening and what I need to do to fix it? I've never taken the engine apart before, so assume I'm a newbie.

And speaking of the engine, is there a repair manual for this mower on the 'net?

Thanks!
 
   / LT133 13 HP engine, gas leaking into the oil #2  
Most likley is the fuel pump it runs off the vacuum from the crankcase ther might be a hole in the diaphragm allowing fuel to be sucked into the crankcase.
 
   / LT133 13 HP engine, gas leaking into the oil #3  
The carb needle valve is not sealing and allowing the gas to continue to run into the carb, overfilling it and then the gas is either leaking into the cylinder, and pass the rings, or down the breather tube into the crankcase. Remove the carb and give it a good cleaning, and install a carb repair kit, check to make sure it is not still leaking by letting it set for a period of time without running the engine. Look into the carb and if it leaking the carb most likely will be full of gas. Then change the oil and you should be good to go.
 
   / LT133 13 HP engine, gas leaking into the oil
  • Thread Starter
#4  
The carb needle valve is not sealing and allowing the gas to continue to run into the carb, overfilling it and then the gas is either leaking into the cylinder, and pass the rings, or down the breather tube into the crankcase. Remove the carb and give it a good cleaning, and install a carb repair kit, check to make sure it is not still leaking by letting it set for a period of time without running the engine. Look into the carb and if it leaking the carb most likely will be full of gas. Then change the oil and you should be good to go.

I recall now that is what the tech said years ago, pretty much. Are there any diagrams of the carb and out to install a carb repair kit? Other than change the oil and filter, I've never done anything with this motor.

Thanks,
 
   / LT133 13 HP engine, gas leaking into the oil #5  
There are alot of carb videos on youtube, just find the one for your carb and it will explain what to do. For the most part carbs are a lot simplier than what most people think they are.

I have done so many over the last 15 years, I can about do one blindfolded.
 
   / LT133 13 HP engine, gas leaking into the oil #6  
The LT133 has a fuel pump.





MP20233________UN17FEB99.gif
 
   / LT133 13 HP engine, gas leaking into the oil
  • Thread Starter
#7  
The LT133 has a fuel pump.

View attachment 275085


Thanks! That looks like it comes out of the service/tech manual. If so, good since I ordered late last week, should be here tomorrow or the next day.

Last question: good place to get a carb kit besides the JD dealer?

Thanks,
 
   / LT133 13 HP engine, gas leaking into the oil #8  
That pic is actually from the JD parts site online, you can lookup parts breakdown for almost any machine there.

John Deere - Parts Catalog

Usually if a machine has a fuel pump, the fuel tank is lower than the level of the carb, a hole in the pump diaphragm would let fuel directly into the crankcase. If the fuel tank is higher than the carb Randy's explanation is correct.
 
   / LT133 13 HP engine, gas leaking into the oil
  • Thread Starter
#9  
I continue to appreciate the help. However, I still have questions; last time I'll make that promise!

From the site that Batty provided above, I find the carb kit as shown below:

MP17618________UN09SEP97.gif

Where in that pic is the potentially leaking diaphragm? If it's the diaphragm like several have said here and that part is not included in the kit since the kit parts list shows several gaskets but no diaphragm, then installing the kit would be a waste of time. What am I missing?

Thanks again!
 
   / LT133 13 HP engine, gas leaking into the oil #10  
I am referring to the diaphragm in the fuel pump not in the carb. Over time both the vacuum operated and mechanical (like yours) pumps can develop a pinhole in the pumping diaphragm and either squirt fuel out of the vent onto the engine or into the crankcase overfilling the oil.

The carb part Randy is mentioning is the needle and seat, looks like #9 on your picture.
 
 
Top