Another 312-8 that won't turn over

[ScottR 5]

I know this is a worn out issue but I'm a newbie at electrical problems.  I mowed for 90 minutes with this tractor yesterday and t it ran fine. It had sat for a few weeks and started on the second crank which is unusual. It normally needs 3 to fire up. It's a 1995 312-8 with the M-12, no indicator lights. I washed it up after mowing staying away from the instruments and motor as I always do.  When I tried to start it nothing happened at all. Just dead.  The lights and volt meter work.  The battery is only a year old, has 12.6 volts and doesn't need charging according to my charger.

The seat, PTO and clutch switches have continuity. The fuses have continuity. I did a cursory check for broken wires and everything looks really good.  Any recommendations on what to check next? I'm perplexed as to why it died after washing, I thought it might be a water problem but it is good and dry now after sitting in my 80 degree garage for 24 hours.

Thanks for any help.

Scott

[gwest_ca-(File Mod) 11,393]

The starter circuit in this file has it's own diagram. Much easier to understand.
http://www.wheelhorseforum.com/files/file/3817-tractor-1995-312-8-wiring-detailed-492-4509pdf/

Garry

Adding
The starter circuit illustrates a low oil condition which opens the the low oil relay which prevents the starter solenoid from being activated.

Edited June 16, 2015 by gwest_ca

[Racinbob 11,888]

Per your words you're a newbie to electrical issues but it sounds to me like you should give yourself more credit. It's a longshot but from what you've checked you might want to try a different battery or jump it. Strange things can happen. Just last week I had an odd one. It was on my truck but the theory is the same. I just got home from a road trip. Stopped my truck in the drive to disconnect the trailer. Went to start it to put it in the garage and it was dead. No click, horn dome light, nothing. The battery voltage was 12.7. Oh oh, I'm thinking. I charged it a while and still nothing. OK, what's happening when I put a load on the battery? Since I was home alone I set up the meter so I could see it from the cab. I opened the door. Voltage now 2 volts. That was just the dome light trying to come on causing that. A new battery solved the issue. What ever happened to a battery giving some sort of warning that it's about to die? Again, it's a longshot but I think a shot worth taking.

[ScottR 5]

I tried jumping the battery with my 314-8 without success.  I'll look over the circuit diagrams Garry provided.  The oil is not low. How would I check the low oil relay for proper function?

Thanks again for all the help.

Scott

[boovuc 1,090]

Hi Scott.
I would disconnect the battery and then with an emery board, go around and brush up the contacts and I mean all the contacts on the tractor. Also make sure the little wire on the little terminal on your solenoid is clean and connected. This includes opening up the dash and cleaning up the ignition switch. Check the starter motor terminals/connections also. Unless you have a dead spot on the starter or your solenoid took a proverbial "poop", it's probably a contact issue.

[Aldon 4,828]

Sounds like a solenoid issue. Since you have lights etc and good battery. Try tapping the solenoid with a wrench or screwdriver handle or something. I have had them stick. I usually play it safe and replace if it then starts but I am overly conservative perhaps.

Edited June 17, 2015 by Aldon

[Wheel-N-It 2,976]

Last week the PTO switch died on my Ariens zero turn from pressure washing. The Wheel Horses have open contacts in their PTO lever safety switches. You may have blown a piece of trash in the switch to hold the starter contacts open. Try blowing those switches clean with compressed air.

[buckrancher 2,694]

check the oil level also you can unplug the motor from the  wiring harness  at the back of the motor that will take the oil level sensor out of the picture the relay only works with the oil sensor and see if she will start

Brian

[ScottR 5]

Thanks for all the great advice guys.  Brian, you had the winner.  It cranks with the motor harness disconnected.  Guess I need to order a new oil sensor if they are still available.  The oil level is perfect.

Thanks again!

Scott

[gwest_ca-(File Mod) 11,393]

Your oil level sensor may just need cleaning but read this service bulletin over. It explains how to remove and instal without damaging it.
http://www.wheelhorseforum.com/files/file/2062-wh89-90-t17-oil-level-switch-servicepdf/

Garry

[ScottR 5]

Garry,

Thank you.  Without this bulletin I would likely have wrecked the float . Hopefully I'll get lucky and a good cleaning will solve the problem. 


Scott

[ScottR 5]

I pulled the oil level sensor.  Question, is the float end supposed to have oil inside it?  Mine is half full with oil.

Happy Fathers Day all.

Scott

[buckrancher 2,694]

no kinda hard to float with oil inside there's your problem
the floating piece has been compromised with oil inside it will sink and activate the switch which will allow 12volts thru the switch to the coil side of the relay opening the points
and stopping 12 volts to the starter solenoid

Brian

Edited June 21, 2015 by buckrancher

[ScottR 5]

That's what I figured.  I'll just have to disconnect the switch and hope to run across a used unit someday.  The part is no longer available. 

Thank you.

Scott

[ScottR 5]

You can find anything on eBay. I got a new in the box unit for, well, for a lot less than it could have been. A little bit more though and I would have lived without it.