425 riding mower no start

Bishop64 · Apr 11, 2019

Neighbor gave me her mom's old JD 425 after she passed away. It has 1100 hours and been sitting for about a year. Last time they tried to start it, it would spin over but not start.

I did the normal prep, new battery, new plugs, cleaned the fuel tank etc. Replaced the fuel pump & line and the time delay module. Still no spark and no fuel, just spins over.

The red & green lights on the circuit board light up & both fuses are good. I'm wondering if it's a safety switch that's gone bad maybe?

Mike M · Apr 11, 2019

Put a compression gage in it and see what readings you get. Those engines if the early ones the cam gear is plastic and prone to fail. Replacements are steel. Does it seem to spin fast ? I kinda forget how mine acted when the gear went out. One day it was fine. Parked it in the garage next time needed maybe a week or less later it would not fire off. I think I could tell it sounded different and spun faster. I think it should still spark though ?

Lee B · Apr 11, 2019

I'm with Mike here - it should be able to make spark by removing the various safety switch grounding schemes to maybe reveal a shorted wire and not necessarily a bad switch. But they do go bad and do that too. Does the carb have a fuel shutoff solenoid on it? If it doesn't get power with the switch then you'll get no gas. But old gas left to sit could have glued the pump's valves shut so that it doesn't work and plugged the carb's passages as well. You'll need both spark and gas so pick your poison. Best of luck with it.

Bob · Apr 11, 2019

So you don't hear the fuelpump running?

Without power to the fuelpump, likely there's no power to the TDM, so there will be no spark, either.

Power for fuelpump comes from the ignition relay in the control/fuse module, which SHOULD be powered since the green LED is on, so I would suspect a relay or circuit board issue, or a wiring or connector issue in the common wiring between the control/fuse module and the TDM and fuelpump.

Some differences by serial number, which you didn't post, as well.

You are probably going to need a manual with a detailed troubleshooting "tree" for this one!

Email me, if you'd like, for more info.

[email protected]

Bishop64 · Apr 12, 2019

I just found a technical manual, that should help a lot.

I'd heard of the plastic cam, meant to pull a valve cover and look. May do that this weekend but it seems to spin with resistance so I'm guessing that hasn't happened - yet.

Not sure about a fuel shut off solenoid but the hose isn't hooked up, just pouring gas down the carb. The pump never comes on. I was hoping to hear it run before tearing into the carb but may have to go ahead.

It's got to be electrical (my favorite nemesis) I think so now with the schematic I can start trouble shooting. If it's the circuit board, can those still be gotten somewhere? Used maybe?

Thanks guys,

buickanddeere · Apr 12, 2019

. Why throw parts at it instead of troubleshooting?
Until the ignition control module is powered with 12V and the pickup coils are sending signal to the module . Nothing is going to happen .

Bishop64 · Apr 13, 2019

Exactly. That's why I was happy to find the technical manual.
So far all I'm out is the $28 time delay module which commonly fails any way. I still have the old one as a back up.

Bob · Apr 13, 2019

(quoted from post at 04:05:45 04/13/19)
Exactly. That's why I was happy to find the technical manual.
So far all I'm out is the $28 time delay module which commonly fails any way. I still have the old one as a back up.

If you feel you can do this SAFELY (safety switches will not be functional and if it starts it won't shut down 'til the power jumper wire is removed), jumper battery power to the "ignition relay circuit" shown in GREEN (even though the actual wire color is pink/blk).

This should power up the fuelpump, the fuel solenoid and the "ignition delay module", enabling spark, and if it cranks, it should now start.

Then, then you can go though the troubleshooting "tree" in the manual and verify if the problem is in the "fuse and relay module", perhaps a cracked solder joint at one of the relays.

Bishop64 · Apr 14, 2019

I got it running but while it was sitting there idling it quit and back to where I was...

I ran through the Electrical System quick test and it all checked out. I haven't scrolled through all 1,000 pages yet so thanks for the Fuel Pump schematic. I'll focus on that now.

While it was running the PTO wouldn't engage so I'll need to look that up too.

Many thanks,

Bishop64 · Apr 14, 2019

It's an early model BTW, -070000.

Bishop64 · Apr 17, 2019

Turned out to be loose connections at the fuel pump too. Running fine once I tighted all those up.

Need to change the trans fluid but can't find any low viscosity Hy-gard 20D compatible. Found JD20A, B & C but no D.

Is there an equivalent or must I go back to John Deere?

425 riding mower no start

Bishop64

Member

Mike M

Well-known Member

Lee B

Member

Bob

Well-known Member

Bishop64

Member

buickanddeere

Well-known Member

Bishop64

Member

Bob

Well-known Member

Bishop64

Member

Bishop64

Member

Bishop64

Member

Similar threads