[jd_400_guy]

Hi guys.. I've followed this site for 4 years now. I love how much information and friendly folks are here, helping one another keep the black sheep running strong. I need help before I pull out my hair.. My john deere 400 bought 4 years ago is having electrical issues. This problem started with a burned up coil once 2 years ago. To now it burns up new coils and solenoids every 3-4 grass mowings. (yard sized 1 acre) I am meticulous with maintenance and try to only buy the best high quality parts.. What it does is seems to overheat the coils, to the point u can't touch them after cutting 1/2 acre. I replaced the voltage regulator, spark plugs, points, condenser, starter solenoid, and many many expensive coils.. And after sitting for a week I went out to cut and fuel pump started up and turned the key to start and slight short sound and nothing.. Has this damaged the starter internals? My battery after sitting for a week it showed 15.1 volts with volt meter.. And slowly checking many times goes to 14.8, 14.3, 14.1, 13.8 ETC…I feel so frustrated.. Like the starters shorting out while I'm sitting there trying to get it to turn over..The JD service manual told me to follow the cranking tests. I tried and everything pointed to a new solenoid.. So I replaced that and now a week later of sitting in the shed. I turned key to on position that engaged the fuel pump. I then let fuel pressure build then turned to crank but won't turn over or do anything. It also makes the fuel pump inoperable even in the key on position when it won't crank anymore also.. Thank you guys for any help or guidance you can send my way to get my beloved 400 back out in the yard mowing again…The only things I have not changed is the key switch because the manual said its getting power to the solenoid so it is good. But key switch, starter, and the stator are the only things that haven't been changed or messed with..Is it possible some knucklehead changed my stator with the wrong sized one causing this mess? Or is it my starter has been shorted out so many times its now constantly like a direct short and until its replaced or rebuilt will continue to burn up the ignition and solenoids? Thank ya'll for any and all your help on this problem… Im terribly sorry this is so long but I wanted to try and show everything and anything it is doing to help with diagnosis.

 

[jdalchemist]

Hi Chris,
Welcome to WFM. You indeed have a very frustrating electrical problem. The strangest part are the high voltage measurements on a "resting" battery (if your voltmeter can be trusted). Try checking your voltmeter on a car battery that has not been charging for a few hours. A good charged 12 V battery that has not been charging for a few hours should show 12.5 V. With the engine running, a charging system will put out about 14.5-14.8 V at the battery posts. A bad battery can cause the voltage regulator to put out excess voltage with subsequent failure of electrical components like ignition coils. Take your battery to an auto parts store for testing if you are unsure about the voltage checks. Is there any chance the polarity has been reversed in your tractor--battery cables reversed? Also, you replaced the condenser, and is it and the wire to the points connected on the same coil post? Is the condenser body well grounded? The key switch and connector are actually one of the first things to check when there are odd electrical problems, but a flaky switch could not explain all the failures.

Harold

 

[jd_400_guy]

Hi Harold..I have the feeling I am attempting to repair CORRECTLY or chase down a repair, a careless previous owner did…What I found out with your advice is this.. My voltmeter is a Greenlee DM-60 (unfortunately made in china).. I clicked it two turns counter clockwise. If u search that name it should bring u a pic of it… Anyways on the tractor its been resting since I tried at 6pm to start it, and its 10:45 now it showed at the posts 13.9 volts with cables still hooked up.. My mustang showed 13.3 volts an hasn't been started for a week…
As for the coil wiring.. What I found out on that is the points and the condenser wire leads go to the same post on the inner side of the coil. The anti dieseling solenoid lead goes to the outer closest to the brake pedals.. I also noticed the voltage regulator plastic connector in the center is melted along with center wire, but still connected and pushed in tight.. Looks like it just got very hot, but that voltage regulator is brand new, I guess I should have fixed that wire correctly when I had the new part in hand.. No need creating new problems, seems like I already have enough to sort out with this cranking problem.. Does a melted center wire going into the voltage regulator indicate a mismatched or bad stator? Like I said earlier it seems to me that its overcharging the battery but I don't know enough about these 400's to know if that problem goes hand in hand or not.. Thank you harold for your help on this I really appriciate your time and guidance on this..

 

[jdalchemist]

Chris,
The connections at the ignition coil seem OK. It appears the voltmeter is reading a little high, but do not worry about that for now. Try checking the battery voltage under load by hooking the voltmeter to the battery terminals and cranking. If the engine will not crank as you mentioned above, try disconnecting the the 3-wire plug from the voltage regulator (in case the VR is shorted out). Now try cranking, and share the battery voltage when the starter cranks.
Harold

 

[jd_400_guy]

I agree the voltage meter is a hair high.. I just took a brand new in box 9 volt battery and checked it and the reading was 10.4-10.5 volts…Does that sound correct? If it should be reading 9.4-9.5..Then that makes my reading at the posts on the tractor 12.9 instead of 13.9 if it is off 1 volt… either way… You mentioned the key switch is the place to start.. I have a brand new one I ordered when I got the new starter solenoid.. But when I replaced the starter solenoid the tractor started and did wonderful, with the exception the coils still got very hot after running a hr to hr and a half under load cutting… That is why I didn't change it because I thought the old solenoid was the part causing all this mess...

 

[jd_400_guy]

Harold.. Wow that was crazy.. I hooked up the leads to the post. It read 13.8…I turned the key to on the fuel pump engaged and the tractor cranked… Well it started like usual with the choke an 2 seconds of cranking..Once started at a low idle it was reading 14.2-14.3.. i accelerated the throttle and as it climbed in rpm the volts climbed as expected.. But when i got to around 3000-3200 rpm it was reading 15.1 As I kept it there it climbed after 2-3 mins to 15.4-15.5…. as i lowered the rpm down to a low idle it was slowly coming down in volts til it stopped declining at 14.5

I am thinking it might just be the key switch having voltage problems since thats the only thing I have never replaced..Do you want me to replace that tomorrow before I do anything else, or would you rather me get it to run again and cut the yard and test something else before changing the key? Either way a brand new solenoid shouldn't stick after only one week and one time of mowing with it i wouldn't think, but new parts now a days that aren't usa made always seem to keep us scratching our heads these days...

 

[jdalchemist]

Chris,
The charging system appears to be working OK, taking into account that the voltmeter is reading about a volt high. I would definitely pull the key switch (easier to get to with the battery removed). Part of the time a problem will be obvious with a pin or connector corroded or burned. Other times things look OK, but internal contacts in the switch are bad. The key switch may not be the only problem, but it should be corrected or eliminated as a problem.
Harold

 

[jameszmcnelley]

hi Chris, Welcome to the 400 squad. Here is a list of things for you to check concerning your coil overheating problem.
#1- is it the right coil? anything rated over 20,000 volts is useless on a {point type} ignition syst. even on V-8s. ''I am sure I opened a can of worms there.'' any way, if you are using a high volt coil you can install a ballast resistor on the bat + side. that will fix that issue.
#2- incorrect plugs
#3- worn plugs
#4-plug gap to wide. {try narrower than fac. spec.}
#5-high resistance plug wires
#6-loose or dirty connection between wire and plug or wire and coil.
one of these may be your issue. I gathered from your post you have good points set correctly and good condenser.

another tip concerning starters and some other electrical issues. on engines with rubber motor mounts. Run a ground strap from the block to the bat. Run another ground strap from the frame to the bat. Don't take this issue for granted.

now for the bad news. voltage regulator plug-in melt down at center wire.
when I got my 400 the po had replaced the reg. it had a semi-melted connector. it was charging. later I installed a new k582. exterior of harness looked good from the stator to the plug-in. But curiosity had the best of me, and since I had it out to install on the new engine, I split the harness open with a razor knife end to end. The center wire insulation was almost all gone. Melted and burned away. It had affected the other wires as well. Miraculously it had not all just shorted out. Replaced all wires and installed new spud connectors. So you might wont to keep this in the back of your mind. Sorry. Good luck and let us know what you find. later, JZM.

PS. For any frog that wants to jump on my 20,000 volt comment, do the research. I haven't got the time for a tutorial. 400 project X is sitting alone in the garage screaming for some attention.

 

[jd_400_guy]

Harold, I will go ahead and pull out the key switch. Look it over and see if anythings obvious on the outside. I'll throw in the new one to eliminate that. I have heard that is the first thing to replace when anything electrical happens to the 400's.. Also I saw a post buy a guy named Tim. He said on another site mother deere has a kit and part number for a relay that is suppose to raise the amps going to the starter.. Have you heard of this JD fix in your travels over the years? Like you said that key can be a totally different issue.. But I had the same prob as another guy. It starts sometimes on first crank and other times could be the 25th try and it will magically crank.. He found that his wire from the solenoid to the starter over time had a "break" in the wire. Causing an intermittent start/crank issue…But we are at process of elimination at this point. I have a intermittent crank condition and once running after a 1/2 acre under load mowing issue of burning up coils.. Which I think might be caused by my key switch telling the solenoid to stay in start mode over heating the whole system as I'm mowing..I will keep you posted as I will try an change out switch and mow today after the football games over.. Thank you once again for your guidance Harold...

 

[jd_400_guy]

Mr. James, Hi and thank you for the warm welcome, to the black sheep cult!! LOL As far as I know it is the correct coil.. I have tried the plastic kohler OEM's part number 277375 ones.. And I have tried the metal type ones…Both types meet their early deaths.. I do know this problem since 2010 when I bought it has over the last 4 years gotten progressively worse and worse.. I use to replace coils and points and condensers once a year- to year and a half to now replacing it all every 3-4 mowings.. And I mow only a acre.. As for plugs I only use NGK, and they are the ones thats called for. The ngk B4L non resistor type.. And that non resistor type was because an older gentleman told me from his years of restoration, to use them instead of resistor ones.. My jd service book does call for either resistor type or non resistor types, only diff is to recap them accordingly i think non resistor was at .035 an resistor was .025 gap…. As for plug wires. I am suspicious cause they look really old an original and firm.. I haven't checked the resistance of them yet. Thats going to be next in line after key switch replacement…I believe the original wide braided ground strap I saw last summer was tight and in place. I had to replace a motor mount bolt that was missing in the left rear side and I noticed the strap then.. Thanks for the ideas and thoughts to look into, James… Go VOLS!!!!

 

[chuckv]

Chris,

Sorry to come in here a bit late, so forgive me if any of this is a repeat of things you may have tried in the past.

First, your starter and solenoid are most likely NOT staying engaged as that would be such a high current draw that your charging system and battery would never keep up...

I have never owned a 400 tractor, just the later open frame units. I do not recall however that engine starting used a different current through the ignition coil as some automotive engines did in the middle of the last century. Those set-ups with a series resistor for the coil would bypass the resistor in cranking mode to get a 'hotter' spark...but I have never seen this discussed on these forums so suspect that the 400 does not do this. Most small engine coils like those for the Onan and Kohler twins have internal resistors, and are not the ones that JZM cautioned about. If you have an aftermarket coil that needs an external resistor, be sure to use one.

I concur with JZM that the overheated center wire in your charging harness is a sign of stress caused by a failed battery or other anomaly prior to your getting this tractor. You should fix this melted wire -- not only could it short to adjacent wiring, but it may have a high resistance section (due to oxidation, thermal breakdown, etc.) that can adversely effect the charging system. If it does have a higher resistance due to these factors, it will continue to overheat -- even with an otherwise fully functional charging system.

Lastly, the reference you saw to the Deere kit for starting woes is most likely the "starter improvement kit" AM107421 which addresses the voltage loss in the many series safety switches in the 300 series tractors. It adds a relay to directly drive the solenoid when the key is in the START position. It is most useful on the later 'solenoid-shift' starter combinations where the solenoid travel is used both to engage the pinion gear and to close the high current contacts powering the starter motor itself. It does help on the older separate solenoid and starter setups as well. Here is some information:

Hope some of this is helpful...

Chuck

 

[jd_400_guy]

Ok guys… What I have found out after making two adjustments before the dang rain ruined everything.. I replaced the key switch with a new one.. The old one had one post on the back of the switch completely covered in rust.. I did what I could cleaning the connector and put di electric grease on the new posts and the connector.. Tried to fire it and seemed to whirl over the fuel pump and starter with more authority and started faster than ever… Like a second it was instantly running.. Well I figured it fixed it so I shut it off.. I went to work adjusting the carb because it always seemed to run lean and hot.. The plugs were always very clean with a brownish grey color to them both.. I checked where previous owner had it.. The high idle screw was out 3 an 1/2 turns out from seat.. And the slow idle screw was out like 3 also.. The book called for 2 turns on the high and 1 and 1/4 on the low.. Then run on fast and find the happy sweet spot on the high one.. I did that… Put it all back together and surprise … Would not crank again.. While trying to get it to crank I noticed the hour clock continued to run no matter what position the key was in .. After grabbing wires checkin connectors I wiggled neg cable and it cranked.. Now Im not sure probably coincidence that it started… It was all tight and had clean terminals and good connection.. I decided to start mowing … I got to mow for 10-12 mins before of course the bad luck I have and the rain starts falling.. But as I mowed for that short time.. I noticed my amp gauge was bouncing non stop back and forth(never has done that before), and my carb adjustment doesn't feel right or sound right.. It has power while mowing but as I'm going it acts to me like its stumbling and burbling…Almost like the carb is holding the motor back from letting it run.. Maybe like its smothering.. The coil seemed to be on the hot side like usual for the little run time I did also… I think I have to have a bad ground somewhere, who knows where…I want to try Mr. James' idea of running two grounds to see if that helps.. I do know the negative battery cable goes from the post to the engine shield, looks factory… And I have a braided ground strap down on the bottom of the motor below the coil… Looks like its a little oxidized and a lil green to it.. I know the green would mean corrosion…Thats what I found out this time..I doubt it was enough run time to get a reading off the plugs to see where I am with carb adjustment.. That thing is so rough from 1/4 throttle until you get to 3/4 throttle.. Prob is in dire need for a carb clean out and rebuild.. Lets hear ya'll's thoughts for what direction to head in this time.. Thanks guys...

 

[grandpajay]

Chris,
I have found that the K582 on my 400 needs about 3 turns out on the high speed jet. I don't remember where my idle adjustment ends up. Jay

 

[jdalchemist]

Chris,
A couple more things now with a focus on grounding and the solenoid circuit. Keep in mind that the starter solenoid body needs a good ground on the frame to operate. So, the battery ground cables to both the engine and frame are important, as James mentioned. There could be a bad connection, short, or safety microswitch problem in the solenoid circuit. Check the connections and integrity of the purple wire that runs from the key switch to the pto safety microswitch, to the hydro control neutral safety microswitch, to the solenoid post. Be certain the microswitches are properly closed mechanically.
Harold

 

[sreynolds]

I second the odd carb settings. I found the factory settings to be whack. I was informed on this forum that they are true and correct. My full-out rebuild of the carb resulted in some really odd settings in order for it to start and idle properly. I'm remembering it was on the rich side.

One thing that really improved the operation/running quality was a valve adjustment soon after the engine was rebuilt. It would pop and miss even with TONS!!!!!!!! of new components. I found that the valves were too loose and when I tightened them up, it smoothed out. But this is an engine with only 170-some hours on it so...............

I have performed many modifications to said tractor of which all I do not recall, thought the factory ground cable to the engine sheet metal was of a real concern for me. I use the engine block as a ground, not some flimsy/painted sheet steel...duh.

In terms of ignition system.......I was fed up so I installed the Kirk's Point Saver Module and twin=pack BOSCH coils. Can't help you troubleshoot the OEM system.

I have never heard of the starter improvement kit after quite a few years of working on this thing. Sounds like it is for folks who have a dead battery...............

 

[jd_400_guy]

Hey guys, I just wanted to update on what I been finding out.. First I found the prev owner used a neg ground cable that was half the thickness of the positive cable. It was in the term connecter and pinched down with the two bolts on the terminal. I found with hood up while trying to crank it would get a shorting out sound so I was able to tighten up that connection. I think that was my intermitant crank problem. I realize I need to go to parts store an get a bigger one.. I do have a issue that both battery cables are black. I hope to gawd that prev owner didn't screw up and hook them up back wards causing the polarity in the stator to screw up.. Reason I say that is because the coil is still getting hot while cutting 1 acre, but I noticed when I shut the mower off after a long cut, that the coil gets a lot hotter for like 5-8 mins AFTER the mower is off and key is out of the ignition.. Why would that keep getting hotter if no power is being sent to it? Very interesting.. I repaired the bad an melted voltage regulator connections and wires an that seems to be fine. (no Change) other than my amp gauge hasn't went all crazy and quit working anymore.. But I guess the last thing to try is a bigger thicker neg cable wire. If that isn't it than it has to be a bad stator caused by prev owner hooking up battery terms backwards right? Thanks fellas for all your ideas and input and previous trials and tribulations.. The older things get the harder it is to keep them going, especially with parts being made cheaper and cheaper just to save a few cent's..

 

[jameszmcnelley]

Chris, Since you used this unit for 2yrs before the trouble started, I don't see a reverse polarity issue caused by the PO. Then your coil troubles start at that point and continue for another 2 years and during that time other issues have piled on. I doubt that they are ALL related.
If your ground issue is resolved. I suspect a short. As you know you have to pull the flywheel to get at the full length of the stator wires.
I have also seen two of the six flywheel magnets come unglued and stick in place to the stator poles.
I want you to try this. Take a test light or an amp meter set low range and connect it to the NEG. post on the battery. The other lead to the block. Do this with key off, then try it with key on, then do it with key in START mode. if you read any current at all, you defiantly have a short some where.
Something is putting power to that coil. I still suspect the stator wiring is your trouble. These test will not necessarily rule in or rule out stator issues. I doubt they will show any current issues or you would have dead battery issues after sitting a while. humor me anyway. Let me know what you find on the tests I mentioned. later, JZM.

 

[jd_400_guy]

James, Hey bud thanks for the test idea. Actually I have had the 400 for 4 years.. Since buying it I have had to fix a bunch of rigged up messes on it.. The coil problem since 2010 has gotten progressively worse. It started burning up a coil once after 2 yrs. I replaced everything and it got to the point of burning up coils now 4 yrs later after mowing an acre 2-3 times before burning out..
What I have found after fixing the negative cable and the voltage regulator melted plastic connector and terminals on the wire connection, is this.. I cut the whole acre an parked it. I could touch the coil durning mowing while running never shutting it off and it was just warm. When I finished and parked the tractor I idled it for like 3-4 mins then shut it off. As it sat there off the coil got so hot especially on the side closest to the left of the coil if your sitting on the mower.. It got so hot to the point I couldn't hold my fingers on it or it'd burn them. After like 5-10 mins it would start cooling off so u could hold your fingers on it. I do know that the factory hour gauge works and when the tractor is shut off (key switch off) the hour gauge continues to run for a bit. Not sure how long maybe a few 10-20-30 seconds, I'd have to time it again I forget how long.. So technically I did not use it for 2 years before all this trouble started, as its been this way since the day I bought it. All I have done is changed oil and trans fluids religiously. filters, a new battery, spark plugs, points, condensers, coils (like 5-6) and recently voltage regulator, key switch, and starter solenoid.. Thats it… So it still is the problem from the previous owner.. And obviously I'm sure the reason why he got rid of it..But heck it's only money and I'll get to the bottom of it evidentially, especially since i have replaced everything with brand new, model specified parts from a sponsor on here, and all that has not been replaced is the stator and wiring…Thanks for ya'lls help..

 

[jd_400_guy]

James I remember you mentioned to try my spark plug gap. And to possibly close the gap even less than factory.. I have not tried this. The factory says .035 for non resistor..and thats where I have them. I replaced the plugs 2 times. When I bought it 4 yrs ago and last weekend.. Both times gapping at .035 like the book said…Maybe I need to try in the .025 to .030 range.. Less spark jump would in theory make you think the coil has to work less hard right? You have a 400 don't you james? And does it have the K532 an non resistor plugs? what do you gap them at? thanks bud..go vols...

 

[jameszmcnelley]

Chris, Yes, a 400 with a new K582 mini block. Same engine, bigger bore. Plugs are Auto-lite 216 non resistor set to fact. spec. My coil appears to be as old as Methuselah.
Until you find this short I recommend you un hook the battery when not in use. Keep you from burning up coils so fast. And possibly from burning up the whole tractor and whatever else is near.
I suffered a total loss of a new home in 88 from fire, and just last week the old man caught an 02 s-10 on fire inside his garage while working on it. Thankfully he was able to drag it out in time with the wrecker before the shop went down too. {we just put in a new shop ceiling the month before, ha.} Truck was a total loss. Fire department couldn't put it out, ha.
What I am saying is this; those electrical fires are SNEAKY. You want know it, until its to late.

Those vols need an effective offensive line. later, JZM.