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Discussion Starter · #1 ·
Please help! I have a john Deere 425. It was running fine the night before the next day it won't start. It is very cold where we are so I thought that was the problem. It was turning over and sounded like it was going to start but nothing. I sprayed some starting fluid in the carburetor and it ignited it but still would not turn over. Finally the battery went dead trying. I let it sit and recharged the battery for two days. Tried again but still nothing. I then pulled the plugs and checked for spark as it did not sound like it was going to turn over, no spark from either plug. I figured it was the time delay module so I replaced that and put in new plugs and still no spark. What now??? I was going to check all the safety switches but I don't think it would be trying to turn over if that was the problem. Any help would be really appreciated. More snow is in the forecast and need to get it running!!!
 

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Bonehead Club Lackey
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There any gas in it? Maybe change gas filter. Check all fuses.
 

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GTT's Pilot in Command (PIC)
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Have you been careful when handling the spark plug leads? If you (or someone else) has been rough with them, they can be damaged and not deliver to the spark plugs.
 
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Discussion Starter · #5 ·
Not a fuel problem it is the wiring I think

Plenty of fuel. It is not getting any spark from either plug when pulled and grounded to the engine. I don't think it is the wire to the plug as nether are sparking. It is definitely in the wiring I just don't know where to start looking or how to trouble shoot it. I was told it could be the ingnition switch which cost $300. I just spent $25 on the delay module that was not needed.
 

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Discussion Starter · #7 ·
In your very 1st post, You stated that the starting fluid ignited. What do you mean by that?
It was lighting the fuel in the carburetor and sounding like it might turn over, then it just stopped. It has not done that again. Now it just cranks. That is why I checked the plugs. Maybe trying to start it so many times I burnt something out?
 

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It was lighting the fuel in the carburetor and sounding like it might turn over, then it just stopped. It has not done that again. Now it just cranks. That is why I checked the plugs. Maybe trying to start it so many times I burnt something out?
Are the plugs wet or dry?

Terminoligy: By turn over, you mean it tried to run on it's own?

Judging by what I'm reading

Try pouring a LITTLE gas in the carb and try it
 

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GTT's Pilot in Command (PIC)
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Has to be the module, or the wires, if I am reading the posts correctly. I read it as turning over quickly, when you say thought it would "catch". If you are not getting spark, if you are pulling each plug and looking at it, and plugs are new, that doesn't leave many things that I can think of. Of course, I am not a master mechanic. I'm barely a shade tree mechanic, at best.

If it is slow to turn, then battery could be an issue. If it turns and you get spark, but not starting and running, think fuel system. That would lead to debris in fuel, filter plugged, etc.
 
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The 425s have a common problem with the connectors at the bottom left side of the engine where the ignitor is. Clean them really well and connect and disconnect them over and over. The terminals seem to lose the connection. If that doesn't help it could be the ignitor which is the box at the lower left side on the engine mount. Clean everything really well and add some WD40 or whatever your preferable treatment is to displace moisture. Good luck!
 
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Before replacing any more parts remove and inspect the spark plugs. If they're wet or fouled clean or replace them and attempt to start the engine.

Check each wiring harness connection for dirt, moisture, corrosion or damage. Disconnect, inspect, lubricate and reconnect each harness connection. This image of the ignition wiring and components may help:

White Text Line art Auto part Design


After disconnecting and reconnecting the harnesses (especially at the Ignitor #31 and the Trigger sensor #5) attempt to restart the engine. Sometimes a poor connection will cause a no-start.

The following isn't from the shop manual but is a logical diagnostic sequence based on my review of the harness and components.

Using a multimeter check for voltage at the Positive side of each coil (#29) with the ignition switched to the "Run" position. You should have ~12VDC.

Check for voltage on the Negative side of each coil with the engine "Cranking." The voltage should vary as you're cranking the engine. If you get this far the Ignitor and Trigger Sensor should be A-OK. Constant voltage on the Negative side of the coil usually indicates a faulty Ignitor or Trigger Sensor. The Trigger sensor can be checked using your multimeter set to a Low AC voltage scale. You should be able to measure 15-40 VAC across the sensor connector (disconnected from the harness) while cranking. If there's no measured voltage the trigger sensor should be replaced. If the Trigger sensor tests OK you most likely have a bad Ignitor at this point.

Moving ahead you'll then have to check the primary and secondary resistance of each ignition coil. Resistance between the Primary connections should be Low, ~ 4-10 Ohms. Resistance between either Primary and the Secondary (Spark plug lead) should be High, ~ 8,000 - 20,000 Ohms.

Hope this helps!

:greentractorride:
 

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Discussion Starter · #14 ·
Big Thank you.

All very helpful posts, thank you all. Special thanks to superglidesport for your indepth instructions. I am away for the weekend but will be working on it on Monday. Wish me luck as we are in for another 6 more inches of snow tonight!!!
 
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