[Worker]

Well, now it's my turn... My John Deere GX345 won't fire.

The tractor will turn over just fine but all of a sudden the tractor won't run. Here's what I've done:
- I replaced both spark plugs.
- I verified spark on both plugs by touching them to the block while cranking and there is spark from each plug.
- The seat safety switch is working but I jumpered it anyway (and I am getting spark as well).
- I don't smell raw gas while cranking the motor.
- I can pour some gas down into the carburetor intake and the motor will fire and run fine for a few seconds, but never stays running (again, I have spark).
- The oil level is just above the full mark on the dipstick (I make note of this because I know some motors have a low-oil cutoff but I'm not sure if there are high level cutoff's, but again, I'm getting spark at the plugs)
- When I remove the fuel line to the carburetor and crank the motor, fuel squirts out.
- When I turn the key to the ON position there is a red and green light illuminated on the control board (not sure what's normal/not normal).
- I removed and cleaned the carburetor. I removed all the jets, cleaned the ports and the float works, etc.
- The bowl had fuel in it when I removed it and as stated above I have fuel flow to the carburetor.
- I don't have old fuel and I've been using the machine daily with no issue until now.
- I bought a time delay module but I don't think this is the problem. If it was this switch I would have no spark (correct?).
- That's where I'm at at this point.

I'm not sure about the emergency fuel shutoff solenoid on the bottom of the carburetor bowl. I assume that when the motor is started that the pin is supposed to retract to allow flow, correct? I don't know how to tell if this is working. How do I test it? There is only 1 wire going to the solenoid. Are the mounting threads the ground and the wire is the positive? Can I just cut off the end of the pin/shaft to see if it will run as a crude test to determine if it's the solenoid that has failed? Should I remove it from the bowl, ground it best I can and turn the key? Should that pin retract when I try to start the machine?

I'm not sure what to try next. I'm scratching my head that I have spark, fuel to the carb, but it won't run.

I hope someone here can help.

Thanks :thanku:

 

[cablenewsguy]

Have you installed the new TDM?

 

[Dave Shaver]

Did you replace the TDM or just buy one? Its the root cause of many issues on these tractors and very cheap to replace.

 

[Worker]

I have not. My thought process is that if the motor will run when I pour gas into the throttle area then the TDM isn't bad. What I don't know is if the TDM regulates the timing of the firing when the pistons are near top dead center. Apparently not otherwise I would not run, or run real rough, when I pour the gas directly into the carb. And, if it wasn't firing when it was supposed to, then I would be smelling raw fuel after cranking the motor over for 20-second intervals.

I also figured that before I just waste $20.00 then I should do more investigation. I know, it's only $20.00, but why waste it. But, I'll probably end up replacing it later today to take that question out of the equation.

 

[cablenewsguy]

I'd still try it, the worst that will happen is that you'll have a spare. I have a spare that I keep in my toolbox cause they seem to go bad when you're the furthest from the garage.

 

[rayjay]

Since your motor runs fine when you pour gas down the carb throat then it's obvious you have a fuel delivery issue. Blocked gas cap vent, trash in the fuel tank pickup tube, clogged fuel filter, bad fuel pump , trash in the float needle seat, bad afterfire solenoid, trash or water in the float bowl.

 

[Worker]

OK. I'm running again and wanted to pass along what I learned/did to get it running again.

First I drained the fuel from the bowl and removed the fuel shutoff solenoid. I grounded the threads on the side of a bolt and turned the key to ON. Nothing. The pin would not retract. (the fuel solenoid pin extends up into the main port in the carb. when the machine is shutoff for a couple of reasons...so you don't get backfires from excess fuel in the carb. and as a safety feature)

Second, since I had a new TDM I installed that. Same scenario. The fuel shutoff solenoid pin won't retract.

Third, I verified that I was indeed getting 12-volts to the solenoid. I was able to get my probe under the heat-shrink to the terminal to verify I had power to the solenoid but it still wouldn't retract when grounded. So, it's a bad solenoid.

Fourth, since my TDM is not bad, I re-installed the original one so I could keep the new one as a spare.

Fifth, I used a pair of side cutters to cut off about 5/16" of the pin sticking out of the solenoid. That way I could still use the solenoid to re-install it to the bottom of the bowl and the pin wouldn't stop the flow of fuel. (I hope my pictures are attached here)

Bingo! The machine started right up. I had one backfire in about 10 start/stop cycles but I think that was because I throttled down and shut down right away. After that I throttled down and waited for the idle to settle out before shutting down. That way I didn't have excess fuel in the system to cause a backfire.

The engine seems to be running better than before too. So, my earlier carb. cleaning was a success as well.

I learned a lot about this 'new' machine of mine so it was all good and it only cost me a TDM ($19.00) and a new fuel filter (I might as well).

Thanks to all that offered help. I APPRECIATE IT.

 

[cablenewsguy]

I'll have to remember that, thanks for the info.

 

[Dave Shaver]

That is good info! Thanks for sharing. :thThumbsU

Are you going to replace the solenoid or leave as is?

 

[Worker]

Right now I plan on leaving it as is. If I don't have a lot of backfires I see no need to spend $60.00+ on that little device that may fail again.

But, can anyone shed more light as to what that fuel shutoff solenoid is really for? Parking on hills? Other? (I think it's for reducing backfires when shutting off the engine at high speed)

 

[Worker]

Well, I've been running with that fuel shutoff solenoid disabled for a couple of days now and I have not had any backfires. I throttle down to idle and shut it off with no backfires for probably 20 start/stop cycles now. FYI.

 

[Dave Shaver]

So does the tractor shut off as soon as you turn the key off now instead of running a couple of seconds like mine does?

 

[Worker]

Mine still delays about 2-3 seconds. I didn't change the Timing Delay Module.

You say that yours shuts off right away? What if you hit a bump and you lift off the seat? Does is shut off because you came off the seat switch? (or don't you have the seat safety switch?)

 

[Dave Shaver]

Mine still delays about 2-3 seconds. I didn't change the Timing Delay Module.

You say that yours shuts off right away? What if you hit a bump and you lift off the seat? Does is shut off because you came off the seat switch? (or don't you have the seat safety switch?)

No mine shuts off in 2-3 seconds also. Just wondered if it changed anything when you "snipped" the solenoid.

 

[ronaldbeyer]

There is a U-tube on how to test the Solenoid. It has to be trained to extend the shut off probe. "Watch the video ." I tested mine with similar symptoms as yours. I was wondering if you trained the solenoid so it was re-tracked when you put in back on the carb if it would stay retracted. When power is applied to it it should extend. I am not sure which way the probe should remain in until you shut the ignition off. Can anyone explain this process from an engineering standpoint? If applying 12 volts extends the probe at shutoff time what causes it ti retract?

I have done everything but remove the carb. I flushed it with Sea foam through the throat and filled the gas line with a mixture of gas and sea foam.It started for a 10 second and a large cloud of white smoke and died. I could not get it started again.

I cvan not see how the gas will get to the carb if there in none in the gas line when I try to start it.

 

[rayjay]

That's nonsense. The plunger is extended by a spring. When energized the windings retract the plunger and fuel can flow to the main well. Any time you are having carb trouble the first thing to do is pull the float bowl. On many machines you can do with without removing the carb and possibly tearing up the carb gaskets which would require a trip to the dealer for new ones [ unless you can make some at home if you have the proper thickness gasket material ].

 

[inspectorudy]

Usually, a solenoid works on a magnet to push it in one direction and a spring to pull it back when there is no power to the magnet. The fact that this engine ran when raw fuel was poured into the carb should have been evidence that it was a problem with the carb. Either a bad/stuck float valve, both jets blocked or the solenoid was not working. The easiest to test would be the solenoid. The hardest would be the clogged jets. I'm glad he found out which it was because it can really be frustrating when you cannot find the problem. The monster would have been with raw fuel in the carb throat and the engine wouldn't run.

 

[findthehumorinthings]

I just fixed a similar thing on my JD 190c. It has a Briggs V-twin 25hp with a Nikki carb.

Wouldn't start. Noticed no gas through the filter. Changed the fuel pump. Then cleaned out the carb. No dice.
Then checked the fuel solenoid. Didn't seem to move when powered.

I was about to clip it or buy a new one...thought I would clean it out and put it back on the carb just to see. Turns out it was just stuck.

Now my mower runs like a Deere again.