x 340

[gdigger]

I bought it 1 year old had it about 2 years now. It backfires when I cut it off, had it in the dealership twice they replaced several things , but can't find the problem. Now they say it want hurt anything. Any one else had this problem.

 

[CHDinCT]

What engine is in that 340? Fuel injected? Somewhat unusual on newer engines. It's more common on the older ones without a fuel shutoff solenoid. Try idling down for a minute before turning the key off to let any excess fuel. clear the carb. If fuel injected, it shouldn't backfire.

 

[gdigger]

Engine says john deare itorqe, tryed when ideled down still backfires, dealer aculey said to keep throtle up to cut off ,to keep from backfireing.

 

[r8nger]

Sounds to me like I might need a valve adjustment.

 

[gdigger]

What should I do dealer says nothing wrong, that is after they replaced several parts and could not fix it. I know backfireing can't be good.

 

[ctlguy]

This is not complete unusual. Was typically the older units that did this. As mentioned above after cool down of machine increase throttle slightly each time until when you shut it off it does not backfire. Typically this cured the issue. I have a tendency to blame todays gasoline on degradation of internal components quicker than they should be but could be wrong, just my opinion. But increasing the throttle should work for shut down.

 

[gdigger]

Yes keeping the throttle up during shut off keeps it from backfireing. But it definately is not older. I'm going to try high grade gas.

 

[Eric Barney]

The backfire would certainly shorten the muffler life. Possibly even split it open.
Your engine has a carburetor. Fuel injection does not appear on anything (with a gas engine) below an X700. In my opinion, fuel injection should be on all gas engines. It is vastly superior to any carburetor setup. All our tractors could be running better, using less fuel, with much greater reliability.

 

[gdigger]

Thanks for the info, what can I do to solve the problem, should I try a different dealer.

 

[Eric Barney]

I am assuming that your 'backfire' is out the exhaust. During shutdown. That means that: (a) Fuel (Hot fumes) is accumulating in the muffler because there is no ignition spark while the engine is turned off. The engine spins for a few revs and pumps the residual fuel into the muffler. (b) Something in the muffler ignites this residual fuel. (Probably some glowing carbon deposits.) The first solution I might try is: Premium fuel with an additive like Sea Foam. It should clear out the crud in the muffler that could be igniting the fumes.

The primary purpose for fuel cut solenoids on the carburetor, is to prevent 'run-on.' It should not have that much effect on a shutdown backfire. I always prefer to shut off an engine while it is idling. The slower an engine turning, the quicker it will stop when it is shut off.

 

[gdigger]

I thought the same, engine should be at low idle for shut down. What does sea foam do, is it added to the gas.

 

[Eric Barney]

Sea Foam is a fuel treatment additive. It is helpful for cleaning valves, and fuel system components. There are several different brands, or types of these additives. But most do the same thing. They remove carbon deposits.
Sea Foam just happens to be a brand that I have seen good results from.

I have always used premium fuel, and a fuel conditioner for my lawn tools. The carburetors, and vented fuel tanks are more prone to corrosion than automotive systems. Automotive fuel injection, and sealed evaporative system fuel tanks are much better protected against moisture intrusion, and evaporative residues. Your car will handle ethanol enriched fuels much better than your tractor will.

Personally, I prefer not to have it in any of our fuels.

 

[gdigger]

Thanks for the info on sea foam.

 

[Eric Barney]

Let us know if it works out.

 

[gdigger]

I will.

 

[JoeDel]

What was the end result? I have an x340 in the shop right now that is having the same problems. I just bought this machine used and I am kind of angry the guy would sell something like this without mentioning it.

 

[gdigger]

There is no end result yet, engine still backfires, talked to dearlership I still have a year of warrenty left, mine is 2009. They said john deere told them what to replace. It's not fixed, and they charged me too pick up, and deliver. They worked on it twice, for this problem, this is my 2nd j.d. first one gave problems that's why I traded for this 1.

 

[JoeDel]

Well since I am paying for my repair out of my pocket maybe they will come up with something. I got an initial call that they found particles in the bowl and water in my gas. I filled the tank when I got the machine and didn't even use one full tank of gas. I never had any fuel related problems before in my life so I believe it was the previous owners fuel. I am selling it when I do get it back and will most likely take a bath on it. I just bought a new X500 and this better be the last tractor I ever have to buy. Good luck. I will keep you posted.

 

[JoeDel]

BTW does your oil smell like gas? Mine does and that is what worried me the most.

 

[rekees4300]

I just bought a new X500 and this better be the last tractor I ever have to buy.

It will be if your age is over 50. The 500 series is significantly better quality than the 300 series.