I'm getting confused Firstly beacause 'your' x300 won't run properly, now it's your neighbour who 'owns the mower'. - Just sayin'...
The saga so far:
My X 300 will run and start good. Other times it wont start at all and sometimes just quits while running. I have found out it is spark that goes. I cant seem to find a parts list or diagram to purchase the control unit under the dash or that small module thats mounted in the side of the engine that kills the other John Deere lawn tractor motors. Any help appreciated and tell me if I'm on the wrong track.
I watched a video and the guy said if you disconnect the black wire near the voltage regulator the mower will start and that shows it is the ecu unit thats bad. Mine will not start with this wire disconnected. Am I getting bad info? Do you guys think its the ecu? Dont wanna be wrong at 70 bucks a pop! Coil and plugs are gapped right. Plugs are new
Put the module in started right up. Mowed most of the lawn. Stopped left it running got back on started mowing and it quit, Wont start again. Any ideas?
At this point - That you could start engine here, move forward, mow grass, park it with the engine running, return and recommence mowing - indicates all is working correctly (with the caveat that the seat switch was likely jumpered by small man (neighbour).)
The machine operated correctly to my reading of it. Then it 'quit' in mid-flow. (?)
More advice followed based upon the new ECU module being not-at-fault:
Appreciate all the help. Pretty good with engines so any help with the basics you can leave out. The fuel pump is spitting plenty of gas and the plugs are wet when it quits or wont start. I have a spark tester and every time it dies I loose spark. I will replace the plugs with new ones that was something I forgot just cleaned them. Again the plugs ( old ones ) are gapped correctly. Coils are gapped correctly and all wires are tight and clean. Disconnected the black wire which I guess takes away all the kill switches and the problem still exists. I will post more tomorrow when I put new plugs in and hopefully a good result and a thank you to all of you who helped me!
Just out of curiosity the neighbor who owns the mower has a jumper in the seat switch so it wont quit when he shifts his weight he is a small man. Could that be a factor? Do these machines have a sequence on what switches must me on or off before starting? I think tomorrow ill remove the jumper too!!!
The seat switch is 'jumpered' at this point.
Then:
Man thanks for all that info!! Here is where I am at now. Cleaned the carb and have 12 volts to the carb solenoid. I took it out and bench tested it plunger works good. Runs great starts right up, As soon as I pull the pto switch mower dies! I checked the deck for binding and the pto pulley. I can turn the deck blades by hand from the pto pulley! I shorted out the seat switch to rule that out. I pulled the outlet hose off the fuel pump and it pumps a ton of gas! Any ideas now? Some mowers I have had when you pull the pto switch unless you jab the choke if there cold they would die. The mower was warm and even jabbing the choke didn't help.
The question was asked and you didn't answer - Do you have the 2 or 4 pin/wire seat switch.?
What did you do to 'short' a switch that was already jumpered?
yes stopped and moving parking break released pto pulled tractor quits
I am wondering about the PTO clutch. It's electric...
not sure if it dies with the old ECU wouldn't run with it.
Correct
Latest update. Tractor starts runs well ran for few minutes then pull pto engine quits and most of the time wont re- start. Plugs are blackish and a little sooty. crank a lot finally restarts run the mower top speed for about 5 minutes driving around turn key off plugs are blackish little sooty. Restart drive around nice and warm and as soon as you pull the pto stalls. Sometimes restarts sometimes not. I'm tearing my hair out! New fuel filter cleaned carb fuel pump spits plenty of fuel float in carb not stuck, valve clearances as well as coil gap and plug gap are correct new ecu unit, grounds and all battery contacts are solid and clean. Backfire carb solenoid bench tested good and has 12 volts with key on, HELP!!!!!!!!!!!
So here we are...
PTO Test Do this sequence first because it required minimal disassembly. Just disconnect the mower drive belt.
Three things to do in the following order:
1. Post how many hours on the meter and the size of the mower deck (2 or 3 blades)?
2. Disconnect the drive belt to the mower deck from the PTO clutch. No mower needed for this next test.
3. Sit on the seat. Turn key to the On/Run position (Do not start the engine). Release the Park Brake. Then... Operate the PTO switch. You should hear the 'Clunk' of the PTO clutch engaging. disengage the PTO stitch. Listen for the 'Clunk' again. Operate the PTO switch repeatedly - You should hear the 'Clunk' every time.
(You won't hear this with the engine running, for obvious reasons.).)
'Experienced heads' reading this will know that I am suspecting the PTO clutch as maybe worn out. (Shorting) Just maybe...
Of course, it may not be.
Still with the mower deck disconnected - have the engine running (I know, it runs 'sometimes') and sit in the seat with the Park Brake released - Then activate the PTO switch. Does the engine cut-out or continue to run?
Next, move onto the:
Cylinder Imbalance Test (Leave the mower deck belt disconnected.)
It maybe your engine is only running on one cylinder. Even on one cylinder they sound like they are running on 2 and rev OK but will lack the power to drive the mower or the transmission. Or both.
Disconnect one spark plug lead. Tie it away from the spark plug securely. Start the engine on the remaining cylinder. It should start. Engage the PTO (with no mower belt connected) and it should continue to run.
Reconnect the spark plug and disconnect the other spark plug. Re-start the engine. It should start and run the same as earlier on the one cylinder. Engage PTO as previously. It should continue to run.
Any variation in engine performance with only one spark-plug connected points you to a cylinder imbalance of power.
Answer
all question points in this post to give us a better idea of the situation you are working with.
