Engine will not start unless you unplug the electrical connection to the mower that connects the engine to the mowers control panel and safety equipment. This connector has 3 wires one of them is white, white is the one when connected won't let the engine start. Of course with the connector un-plugged the engine runs fine but I can't engage my blades with the white wire disconnected, I think the problem is an expensive module that I have already re-placed once since I've owned this mower ( I've had the mower since 1997) If anyone has any tips or ideas or links to wiring diagrams I would appreciate it! This is the ser# Gx1320x011071 14hp comm mow

what your asking for help with is a huge safety issue and if anyone here would give you that advise would be opening themselves up to a huge liability. what i would do first is start with each safety switch and find out if one has failed.this is easy enough to do by bypassing the switch (for testing only) to find the one that maybe at fault.if you have a bad one replace it and return the wiring back to the original connections. if none are at fault then you can check and make sure all of your wiring is intact. after all of this is said and done them you can lean to the module. bypassing it is not the an answer, replacing it is...... safety first!!!!

Thanks for the response! I don't know of any switches on this mower that are designed to kill the motor, the only safety feature disengages the blades.

What is model of the mower you have?

The only thing I can find is a plate with the serial# and 14hp comm mow see 1st post, it is the yellow deck crank-up design that came out in the early to mid 90's. Also I've elmiminated the ignition switch as the problem.

Well I might be able to help you trouble shoot the problem, but not without a model number to let me know how your unit is set up. Perhaps if you posted a picture of your mower someone may be able to identify it.

Here's a link to a pic http://www.j-thomas.com/catalog/108_johndeere_crank_deck_parts.html
Heres one on ebay http://cgi.ebay.com/John-Deere-48-commercial-walk-behind-lawn-mower_W0QQitemZ110380746834QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item110380746834&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50

Well I think I found a breakdown on a mower like the one pictured on ebay. I have never worked on one like this, but I do not see any module on this one that would interfere with the engine running. This one appears to have a couple of operator presence switches and a relay. I would test all the switches for continuity and make sure they all the grounds to the wiring harness are good. Maybe someone with JD experience will chime in.

The module I'm reffering to I believe is a regulator it has heat sink fins and is mounted on the mower between the motor and the gas tank, there is also a big capacitor located next to it. I have since figured out what wires to jump to excite the blade clutch, so I was able to use the machine today, this is actually my back-up mower my primary mower is very sick, you will here more about it when I can get time to tear it down. THANKS for your help! If I could get a link to that breakdown that would help, I think the problem is either a bad relay or this module/regulator. Also mine has two relays, and one of them I have unplugged so that the engine will run and to expose the wires I need to engage the blades.
P.S.
Did the breakdown give you a model # ?

That part is a rectifier and it will not interfere with the engine running when the blades are engaged. It is a completely separate circuit from the ignition. It sounds like you have an issue with your safety interlock system.

THANKS! for the help! It's probably the relay that I have disconnected, guess I'll try to price one. The only safety feature this mower has is a dead mans handle that dissengages the blades when released, and this feature is still working even with the relay disconnected.