Tractor Surges With Out the Choke

[liammulloy]

I have an LT1000 that is several years old. I don't know the exact year but I would guess early 2000's. I got it used from my neighbor, he left gas in it for three years!!! I need to run it with the choke pulled about 1/3 to 1/2 way out. If I do not, after a short amount of time, the tractor will "surge" is the best way I have to describe it. Sort of rev up and down while it is running. Any idea what I need to look at regarding this issue. I have cleaned the air filter and the carburetor. On the carb I cleaned the fuel bowl. It is still running about the same, surging in and out without the choke on. I don't know what to do because i now think that it is the air and fuel mixture setting but i don't know how to change it. I have the 20hp v-twin 407677-0229-E1.

I hope some one can help

Thanks Liam

 

[KubotaSam]

If it will only run correctly with the choke out, it means the carburator is not allowing enough fuel to mix with the air. The old gas that was left in will plug the small passages inside the carb. You need to rebuild the carb not just clean the float bowl.

 

[VitaBene]

Before rebuilding I would try to adjust. I usually start the process by tightening the mixture screw completely then loosening it 1 1/2 turns, then fine tuning by ear.

If you are nervous about doing it, determine how many turns to all the way in, then you can adjust back to that setting.

 

[liammulloy]

how does one go about rebuilding the carb? I had all the parts off and sprayed them with carb cleaner, as well as ran the tractor dry and added new gas.

 

[mostly_gas]

Try some fuel injector cleaner or Seafoam. You like have varnish built up in the jets and passages of the carb. If it were mine, I would get a can of carb cleaner that would let you soak it for a for hours or overnight. then blow it out and verify no blockage at the needle valve. Verify good fuel flow, replace the fuel filter. You should see much improvement after doing all that.

 

[tcartwri]

There is nothing to 'rebuild' on these carbs, except to clean them.

The governor on these motors sets the idle as well as the high speed operation. That is where you should be looking.

See the following post, and more specifically the file attached.

http://www.tractorbynet.com/forums/2398905-post5.html

 

[Snaker]

I've messed with a few engines with with those symptoms and attributed it to ethonal. The fuel level in the bowl is critical. I found that the foat needle valve would stick in the inlet hole and not allow proper fuel level. If yours has a small wire retaining clip attaching the needle to the float, bend the clip snug so there is no slop and the float will pull the needle down.

 

[Soundguy]

assuming gov is ok.. I'd check the fuel obstruction issue if it is hunting.

soundguy

 

[Jim Thompson]

Varnish buildup in carb from leaving old gas in it. Remove, disassemble, clean and reinstall. Most everything else will be a waste of time. You can try solvents in the fuel system and may get it to run half way decent, but you'll eventually remove the carb to clean it anyway if you want it to run right.:thumbsup:

Jim

 

[djradz]

As others have said, clean the carb, or clean and rebuild the carb. Hunting often is cased by at least one of the normal ports being plugged. The fact that you can correct the issue by running with it choked seems to confirm this.