Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

Need Help ST16 DEAD


  • Please log in to reply
22 replies to this topic

#1 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 04, 2011 - 05:03 PM

ST16 A.K.A "Lazarus" Has Suffered a Setback.
It just cut out on me today after starting & running perfect. My Diagnosis Turned up 2 strange things...Insulated terminal on Coil is Grounded and Insulated Terminal on Started Motor is Grounded.
FYI : This is a 16HP Tecumseh with Solid State Ignition.
Would sure appreciate it if you guys would Please watch the attached video & help Me Bring Lazarus back From the Dead...AGAIN!!!
‪HELP: SEARS SUBURBAN ST16 AKA LAZARUS DEAD‬‏ - YouTube

#2 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 04, 2011 - 05:13 PM

The green wire: hold the terminal between your thumb and finger tightly. While someone else turns it over, you should feel a tingle. I usually touch my pinky to the block to insure I feel it. Not bad, just don't jerk your hand into the flywheel. If you don't feel the tickle, unplug the connector shown in your video just above the starter and try again. One of those wires are the spark ground out... You may be dealing with a partially bad switch, at least this will tell us for sure.

Do these 2 steps and let us know what you've gotten. Good luck.

#3 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 04, 2011 - 05:29 PM

I did test that Green/Coil Ground Wire and with the Key OFF it reads Grounded, with the Key ON it is NOT Grounded. I don't find anything wrong with the switch...in the on position the Amp Meter & Lights work, it starts fine too. I am NOT very familiar with these Solid state ignitions at all but I don't want to go buy a Coil until I'm sure that's what it is but I can't think of any reason why that insulated terminal, with No Wires attached to it, should read Grounded????

FYI: The Engine Model # is 143640012 Tecumseh 16 HP

Edited by DanO, August 05, 2011 - 10:01 AM.


#4 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 04, 2011 - 06:28 PM

The continuity checks out OK, but is it making juice? The best way to tell is the procedure above.

I don't think the CDI should be grounded, but I won't be close enough to one to tell for sure until tomorrow nite. One other thing, the test lite is a great tool for some things, but with the Solid State stuff, you would be much safer with a Digital Ohm Meter. Less chance of causing a problem while looking for a different one.

#5 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 05, 2011 - 12:20 PM

No Good. Tried your "Hold the Wire Test' Nothing at all. Even touching a ground with my finger. I then Unpluged the Ground wire from the connector, Nothing. Even tried Unpluging the whole thing, No Spark. been looking at these coils on line and they are Crazy Expensive, there's a used one on Ebay now up to $36. Gotta keep plugging away at this until I'm positive it's the coil.

#6 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 05, 2011 - 05:10 PM

No Good. Tried your "Hold the Wire Test' Nothing at all. Even touching a ground with my finger. I then Unpluged the Ground wire from the connector, Nothing. Even tried Unpluging the whole thing, No Spark. been looking at these coils on line and they are Crazy Expensive, there's a used one on Ebay now up to $36. Gotta keep plugging away at this until I'm positive it's the coil.


If you were hanging onto the wire that goes to the pickup under the flywheel, you should've felt a tingle. If you didn't, I wouldn't suspect the CDI ... Yet.

That wire supplies voltage to the CDI which charges and discharges creating a spark. (triggered by the pins on the flywheel)

Some of them used positive voltage, some negative, some just put out AC... Can't mix and match (as far as I know) From what you're telling me, I would take the flywheel off and check for broken wires or , more probably, shorted ones back there.

#7 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 05, 2011 - 08:34 PM

I did finally get the chance to measure a running engine. The wire that goes down behind the flywheel to ground was 486 ohms cold and 503 hot. The CDI measured infinite resistance reverse polarity. It was 1118 cold and 1133 ohms warm.

I still think you are going to find a short behind the flywheel, but I am really wondering why that light lit on the CDI pin. 1133 should be enough to make that light very dim.
  • DanO said thank you

#8 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 05, 2011 - 08:45 PM

Took the Flywheel off tonight & here is what I found so far...Quite the Mess...nothing obvious broken yet but I Gotta Clean it all up tomorrow and have a closer look. Pics & Video attached.

Thanks so much for all your help on this.

‪SEARS SUBURBAN ST16 AKA LAZARUS IS DEAD Part 2‬‏ - YouTube

Attached Thumbnails

  • DSC02745.JPG
  • 100_2646.jpg
  • DSC02747.JPG
  • DSC02748.jpg


#9 DH1 OFFLINE  

DH1

    Electric Tractors

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 62
  • 4,587 Thanks
  • 5,295 posts
  • Location: Markham Ontario Canada

Posted August 05, 2011 - 09:30 PM

This is what the manual says on testing, servicing SSI units. HH100, 120.
Looking at you pictures I don't see any wire hooked up to the small terminal on the coil, upper left corner of the SSI unit
If that wire is not there no spark.

MF10, 12 manual 004.jpg

Attached Thumbnails

  • MF10, 12 manual 002.jpg
  • MF10, 12 manual 001.jpg


#10 DH1 OFFLINE  

DH1

    Electric Tractors

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 62
  • 4,587 Thanks
  • 5,295 posts
  • Location: Markham Ontario Canada

Posted August 05, 2011 - 09:56 PM

ST16 A.K.A "Lazarus" Has Suffered a Setback.
It just cut out on me today after starting & running perfect. My Diagnosis Turned up 2 strange things...Insulated terminal on Coil is Grounded and Insulated Terminal on Started Motor is Grounded.
FYI : This is a 16HP Tecumseh with Solid State Ignition.
Would sure appreciate it if you guys would Please watch the attached video & help Me Bring Lazarus back From the Dead...AGAIN!!!
‪HELP: SEARS SUBURBAN ST16 AKA LAZARUS DEAD‬‏ - YouTube


1- DO NOT APPLY 12VOLTS+ TO THE SSI UNIT EVER if you do you will burn it out.
Testing the coil as you say might give the results you get, not sure.
The SSI unit gets energy from the stator coil under the flywheel, the wire must be on the coil to get spark, if you take the wire off the coil for sure you will get NO spark.
If you remove the spark plug and turn the engine over by hand you should get spark with the wire on the coil and the key switch on.
From what you say you key switch is good.

2- Testing the starter as you say with a test light will give the results that you get, the light will light.
The starter gets battery power from the solenoid to turn, if you measure resistance with an ohm meter across the starter (insulated terminal to ground) you will get a low resistance, that is normal.

Edited by DH1, August 05, 2011 - 10:03 PM.
spelling

  • MH81 and DanO have said thanks

#11 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 06, 2011 - 12:04 AM

Doug, thanks for that page. I know that VOM and DMM units are much less invasive on these systems, just good to see it in print.

I believe the wire was hooked up prior to the engine quitting. It was only disconnected for troubleshooting purposes if I remember the video correctly.

Does anyone know of a way to test to see if the SSI/CDI is damaged except to put it on a known good stator? After reading that I am little concerned that the test light in the video may not have buffered the voltage enough.

DanO, if you don't find anything broken or shorted in there, we need to get a meter involved. Either old style with a needle, or a newer Digital style.

Edited by MH81, August 06, 2011 - 12:10 AM.


#12 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 06, 2011 - 08:03 AM

Thanks for all the Great info guys, I will be cleaning that mess up and unless i find anything else in there broken, will reassemble it all and give it another try. I Gotta say, Although frustrating, this most certainly has been very educational.

#13 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,269 Thanks
  • 28,607 posts
  • Location: N. W. PA

Posted August 06, 2011 - 12:07 PM

Although frustrating, this most certainly has been very educational.


I have never heard a better definition of the word "Hobby" LOL

#14 DH1 OFFLINE  

DH1

    Electric Tractors

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 62
  • 4,587 Thanks
  • 5,295 posts
  • Location: Markham Ontario Canada

Posted August 06, 2011 - 02:03 PM

If it was running and just died then SSI is a strong possibility.

From what I gather and have done myself there's basically 2 steps.

1 - Disconnect the wire from the SSI unit (the wire that goes under the flywheel to the stator) and measure the wires resistance, should be 400 ohms or more with the key in run. That test the stator coil good or bad.

2 - If the stator coil is good hook the wire back up,
pull the spark plug,
hook up the wire to the plug and ground it,
turn the key on,
turn the engine over by hand quickly or with starting motor and you should get spark. If no spark SSI unit is bad.

I got myself one of these spark testers and find it useful in checking for spark quickly without removing the spark plug. It's kind of a gimmick thing but it was cheap to buy and it works.
66 MF10 085..jpg

BTW DanO I like your videos, you got lots of them.

Attached Thumbnails

  • 66 MF10 084..jpg

  • DanO said thank you

#15 DanO OFFLINE  

DanO

    Greasemonkey

  • Senior Member
  • Contributor
  • Member No: 1918
  • 153 Thanks
  • 350 posts
  • Location: catskill Area of NYS

Posted August 06, 2011 - 08:33 PM

Well guys it's been raining all day so I didn't get a chance to check anything out today...maybe a good thing, sometimes you just gotta walk away from it and think......
This Also can help to avoiding a Divorce ......
Doug, thanks for the pic of the spark tester, I actually have one of those on my Jeep that I forgot about. I'll have to use that when I test it. I have a Multi tester and so I will use all the info you guys have given me and check everything out asap and get back to you.
Glad you like the videos, I hope the next one will be of Lazarus Alive & Running again!

You Guys have been Great helping me through this, I really appreciate it very much.




Top