Won’t start

[Volant1006 41]

Went out to take the deck off & put the plow on for winter.  Went to start the 312-8, it tried to turn over, than nothing.  Had this issue before from sitting.  Hooked up a jump pack at it would start right up.  Not this time.  With the jump pack hooked up it just cranks & cranks but never turns over.  It has gas in the tank, fuel in the filter.  Tried spraying some starter fluid, still nothing.  Cleaned the spark plug up a bit, still same issue.  Any ideas of what to try next? 

[gwest_ca-(File Mod) 11,936]

Do you have a visible ignition coil with a coil wire going to the spark plug? If so clean the ignition points contacts. They will get an oxidized coating on them preventing an electrical connection when closed. A nail file will get the job done and then drag a clean strip of paper through them a few times to drag out any contamination.

[Wishin4a416 2,441]

I dont understand what you mean it cranks and cranks but doest turn over. Do you mean start? If so pull the air cleaner and spray some gas directly in the carb throat with a spray bottle. I got one that does that and it is getting a new electric fuel pump. Like said above check for spark.  Good luck.

[Volant1006 41]

I will try to check for spark tomorrow.  I replaced the spark plug but did not resolve.  
And yes it cranks but does not start

[953 nut 63,731]

4 hours ago, Volant1006 said:

it tried to turn over, than nothing.   Bad battery or battery cable ends may be corroded or not tight, check grounds too.

Is the engine a Magnum or a K series?

[Volant1006 41]

1 hour ago, 953 nut said:

Is the engine a Magnum or a K series?

Magnum.  When I turn the key the headlights turn on and are bright.  I’ll double check the battery connections

[gwest_ca-(File Mod) 11,936]

With a Magnum you have no points to clean and the magneto ignition in the Magnum very seldom fails.

You ignition is self-powered and to shut it off the magneto/ignition wire is grounded. Never allow any battery power into the ignition wire - that will release the magic smoke.

With the ignition on and the engine not running are any of the idiot lights illuminated? If so that is the circuit at fault. Ignition is controlled by the pto switch (pto must be off) and/or operator must be in the seat to keep the ignition wire from being grounded which shuts off the ignition.

Down load this 5 page file. The ignition circuit has it's own diagram.

 

[iwuzheerlater 1]

Order of ops,simple stuff first.you took the mower deck off,and were you able to get it in the shed?if so,fuel or elec issue.if you couldn't even start it RIGHT after you took the deck off,you likely knocked a safety switch off the pedal or smth.

[953 nut 63,731]

On 12/1/2025 at 9:36 PM, Volant1006 said:

Magnum.  When I turn the key the headlights turn on and are bright.  I’ll double check the battery connections

[Volant1006 41]

The last time the tractor ran was in the summer, the last time I cut the grass.  That was a few months ago.  I took the deck off the other day and when I tried to start it, that's when I started having the issue.  I replaced the battery since it was 7+ years old to be safe.  Did not resolve the problem.  The idiot lights on this tractor never worked ever since I got it 10 years ago, never thought anything of it.  I did notice 2 red wires behind the battery that looked like they might have been connected at one point.  After hooking up the new battery and the tractor not starting I connected the 2 red wires.  When I did the PTO Clutch light lit up (even with the key in the off position).  Did not affect the tractor not starting so I disconnected them.  

 

 

[lynnmor 8,445]

Remove the spark plug wire and connect it to a spark plug.  Lay that plug thread on a metal part of the engine and run the starter, you should see a spark jumping the gap.  Report back.

[Blasterdad 3,151]

17 minutes ago, Volant1006 said:

When I did the PTO Clutch light lit up

 

Is the PTO engaged? That will make it not start. Also, NEVER use starting fluid, use gasoline in a squirt bottle. 

[Volant1006 41]

Well I went back out to check the oil since I read there is an auto-shutoff if the oil is too low.  It was on the low side so I added a little.  Tried to start cranks, still won't start.  Then after a few times I tried the key again and got nothing.  Won't even make a sound when I turn the key now.  Headlights won't turn on when I turn the key to the on position now either.  PTO is disengaged.  Sitting on the seat with foot clutch pushed all the way down when trying to start.  

[953 nut 63,731]

[sqrlgtr 1,998]

 Wasn't too long ago I bought a new name brand battery for a Wheel Horse and it was bad when you put a load to it. 

[Volant1006 41]

OK, so I tightened the battery terminals up snug (they were a little loose).  Engine started cranking again.  Still won't start.  I pulled the spark plug wire off and inserted a spark plug.  Rested it on the top of the engine block (metal cover).  I did not see any spark jumping the gap.  

[Gasaholic 346]

20 minutes ago, Volant1006 said:

OK, so I tightened the battery terminals up snug (they were a little loose).  Engine started cranking again.  Still won't start.  I pulled the spark plug wire off and inserted a spark plug.  Rested it on the top of the engine block (metal cover).  I did not see any spark jumping the gap.  

Make sure the metal is not painted - spark wont go through the paint. One way to do it is find a flat screwdriver that wedges nicely in between cooling fins and ground the plug to the screwdriver shank .. if you have a couple alligator clips big enough you can clip one end to the spark plug threads and the other to bare ground (cooling fin without paint maybe) , but ideally you'd go on amazon and buy a simple spark tester made for small engines that has a terminal that fits in the spark plug boot and has a lead that clips to bare ground - if you get ANY spark (color depends on ambient air, blue or yellow, it don't matter) then your ignition is good, so then I'd suggest a *KNOWN GOOD* spark plug - They (especially CHampion) are notorious for fouling short to ground... and "new" does not mean "good" . I have had spark plugs (of pretty much every brand) that are internally shorted right out of the box. 

[953 nut 63,731]

7 hours ago, Volant1006 said:

  I pulled the spark plug wire off and inserted a spark plug.  Rested it on the top of the engine block (metal cover).  I did not see any spark jumping the gap.  

Do you have another spark plug wire?

[Volant1006 41]

Figured out the problem.  Apparently when a mouse builds a nest under your engine cover and chews through your spark plug wire it's hard to get a spark.  After taking some things apart I found a dead mouse and his giant kingdom he build in my engine.  He chewed right through the plug wire.  Luckily I had my nephew with who had a friend close bye with a new ignition coil.  We were able to replace the part, tape up some exposed wires and the horse was purring like a kitten.  My shed isn't mouse proof, I feel like I let the tractor down, she deserves better.  The 312-8 has been moved to my attached garage and has the blade and chains on waiting to tear through Snowpocalypse 2026!

 

 

 

 

Edited 11 hours ago by Volant1006

[Retired Wrencher 6,329]

I use this on and around engine when in storage. And other areas of the tractor. I even use it for the truck engine apartment.

[Sparky-(Admin) 24,386]

1 hour ago, Retired Wrencher said:

I use this on and around engine when in storage. And other areas of the tractor. I even use it for the truck engine apartment.

 

  I do the same. I give a shot or two right into the flywheel screen while it’s running at a low idle so that it gets distributed under the engine shrouds. And of course it also gets on any wiring under the shrouds. 
 

[sqrlgtr 1,998]

11 hours ago, Volant1006 said:

Apparently when a mouse builds a nest under your engine cover and chews through your spark plug wire it's hard to get a spark. 

 

get ya one of these for mousey problems...... 

Edited 3 hours ago by sqrlgtr

[Volant1006 41]

44 minutes ago, sqrlgtr said:

My cat's too old.  He just lays around on his candy ass all day looking out the window.  He used to be an arctic cat going out in the snow, chasing everything.  Now he just pony's up by the coal stove and sleeps.   Summertime maybe I'll put him in the shed and see what he can comes up with!  Definitely gonna try some of that spray though

 

44 minutes ago, sqrlgtr said:

get ya one of these for mousey problems...... 

 

[Retired Wrencher 6,329]

1 hour ago, Sparky said:

  I do the same. I give a shot or two right into the flywheel screen while it’s running at a low idle so that it gets distributed under the engine shrouds. And of course it also gets on any wiring under the shrouds. 
 

So does it work for you?

[953 nut 63,731]

I had an in and out cat that was a great hunter, he would catch mice, snakes, chipmunks, birds, you name it. Only problem is he would bring them in the house, turn them loose and play with them until they found a hiding place under the stove or refrigerator. I had traps set to deal with the escapees, I finally put him on a curfew, After supper he stayed in the house, after breakfast he was free to hunt and could sleep in the workshop.