72 JD 400 WILL NOT IDLE

flacker36 · Post by **flacker36** » Sat Feb 02, 2008 8:41 pm

Can anyone tell me the Jd part # & manufacturing # for my ignition generating coils (under the flywheel). My sled is a 72 400 with ccw 340 engine with a serial # of less that 11,000.

Are they still available new? Central??

Thanks,

Joe

400brian · Post by **400brian** » Sat Feb 02, 2008 9:17 pm

'72 400 ignition coil: JD no: AM52368 CCW no: 18000461
JD no: AM52379 CCW no: 18000721

Available from: ebay, MN Vintage Snowmobile, ask here on the list.

flacker36 · Post by **flacker36** » Sun Feb 03, 2008 11:31 am

Brian - There are 2 small ignition coils under the flywheel, are you saying each one has a different part number? Is one of these the lighting coil number??

Local JD service recommended replacing both of these coils. He stated that even if the resistance checks out ok, when they heat up the resistance changes if they are bad. He also informed me that he never had good luck with aftermarket points & to only use factory points if you can get them.

Have you ever timed these engines with a timing light?? I am planning on timing it with the dial indicator & test light & double checking with the timing light.

This machine was used by mice & rabbits for the last 8-10 years in northern Wis. Once I get this engine to run properly, she will be ready to be put back in service.
Looking forward in going north for the maiden ride.

Joe

HoosierDeereMan · Post by **HoosierDeereMan** » Sun Feb 03, 2008 12:16 pm

I think using a dial indicator and test light is the most accurate. Since you must time both cylinders on the points engines there really is no other way. On the CDI motors you only need to time #1. So the light works a little better in this application. I always paint the timing mark on the flywheel so I can better see it. There is also enough distance between the timing mark on the fan tower and the timing mark on the flywheel that it leaves a margin for error depending how you are looking at it. The timing light is good for double checking.

I would still use the light after you get it running again. A inductive light it will tell if the cylinder is firing. If it is, it pretty much leads you to believe that it could be a bad/weak spark plug or that the plug wire is not making good contact with plug boot. If its not firing then you have to work back the other way. Check the plug wire where it screws into the external coil. I've had a few burn the screw off in the coil causing the spark to jump until it burned up and caused a miss. It sounds like you've been about everywhere else from there.

flacker36 · Post by **flacker36** » Sun Feb 03, 2008 12:40 pm

Thanks Troy! Good advise.

I still need cleaification on Brians part #s for the ignition coils before I can get them.

Joe

400brian · Post by **400brian** » Sun Feb 03, 2008 3:26 pm

If we are talking about a '72 400 ignition system, those are the numbers, taken from my '72 parts book.

In '72 there was a separate coil for each cyl. In later years it was a single coil with two wires.

The lighting coil is at the bottom of the stator, and is a different number.

JDXspec · Post by **JDXspec** » Sun Feb 03, 2008 3:34 pm

I believe the reason for 2 different numbers is that one has a red wire and the other has a white wire to ID which CYL they provide spark for

flacker36 · Post by **flacker36** » Sun Feb 03, 2008 4:48 pm

So each small ignition gernerating coil (under flywheel) has a seperate JD & CCW part #. (Jd # AM52368, CCW# 18000461) (Jd # AM52379, CCW# 18000721)

The coils look the same except that one has a longer wire to get to the condenser. No part number on the coils themselves.

Thanks,

Joe

flacker36 · Post by **flacker36** » Fri Feb 08, 2008 9:24 pm

Update. Bought a new stator plate with everthing on it. will try Sat. & get back with you.

Sorry to say I will be working on my machine instead of riding it this weekend up in St. Germain. Maybe next time/next year!!

Joe

flacker36 · Post by **flacker36** » Thu Feb 14, 2008 9:09 pm

Great news!! I put the new (35 years old) stator plate on (cleaned up of course) this weekend. Took the carb apart again & double checked. Put is together & it fired right up. The machine will sit and idle at 2400 rpms for as long as you leave it. I did adjust the carb several times to get it just right.

Bottom line - I really don't know if it was the new stator plate or the adjusting of the carb. It runs & runs good so it's goin north soon.

Thanks for all the help!!!!!!!!!!!!!!!!!!!!!

Joe

smitfire · Post by **smitfire** » Fri Feb 15, 2008 12:00 am

great to hear this

400brian · Post by **400brian** » Fri Feb 15, 2008 3:29 am

I suspect it was the ignition. The Walbros get blamed for a lot of stuff that is not carb related ( in my opinion ).

Glad to hear of the success.

HoosierDeereMan · Post by **HoosierDeereMan** » Fri Feb 15, 2008 9:55 am

I had to laugh at your last post Brian. All I can think of is Paul making the same Walbro comment over and over again while at the HOF.

Danzig · Post by **Danzig** » Fri Feb 15, 2008 2:07 pm

Guys....guys.....ooooooohhhhhhh Guys!!

He hasnt tested the Walbro eater yet.

flacker36 · Post by **flacker36** » Fri Feb 29, 2008 11:02 pm

UPDATE!!!!!!!!!

The wife & I took the 400 up to Minocqua, Wis last weekend & had a Blast. I still have carb issues, but she ran great. I plan on goin up again next weekend. I would really like a 72 500 to go with it for next year.

Joe