D15 Series II runs terrible

Good evening all,

Had trouble last year with our D15 running poor.  Random misfires, stumbling, etc.  Fuel delivery appears OK - no smoke, plenty of fuel to the carb.  Didn't tear it down though; because, I pulled the points, polished them with some 400 grit paper, and that cured it.  Ran like normal.

This spring, same deal again -  it got worse over the winter -  I said "the heck with it" and bought a set of the "house brand" points from TSC and put in it.  Ran great, again, for a little less than an hour.  This afternoon, I started it up, put the bushhog on, and after 2 minutes it was doing the same thing.  Limped to the shop.

Distributor cap is not cracked; rotor button is new, condenser and points are new, gapped to 0.020.  I burnished them just a little and it's running better but not well or "right".

Got a good set of plug wires on it.  Coil is "I-don't-know-how-old".  12V positive ground electrical system - factory.

What gives?  Just that TSC points are junk?  There's less than 45 minutes of run time on 'em. 

Open to suggestions as far as replacement - upgrade.

Agreed with D series 4. I had this one time on my D-15. And then over time got worse. Definitely a head scratcher. Then boiled out the carburetor and it was a brand new tractor!

Sounds like a coil problem to me. 

Thats where our D17 got me Creston, it had a bright blue spark, but wasnt enough to make a spark in the engine compressed cylinder! Go figure! lol

I had similar problems for a while till I figured out that a neighbor was stealing gas and replacing it with water....  Good Fences are a must.

There are a lot of good ideas to check listed. My thought would be more in line with Jim D. Make sure you have a internal resistor coil, and that is wired correctly according to system wired for positive or negative ground. If you are wired for positive ground the wire from the coil to distributor should be attached to the positive post of the coil. If it is a negative ground system, the wire to distributer would be on the negative side of the coil. As far as the resistor coil, an old mechanic diagnosed a similar problem for me. He said these point systems were designed to run on 6 volts. Run them on 12 volts and you will continue to burn the points. Also some of the older tractors had a ceramic resistor that reduced the voltage to the system.

I would just say check the wiring in general and the key switch.   My d17 gave me a hard time this spring I had to have someone look at it about the same story but it turned out to be a bad key switch
My d15 is getting rewired because the wiring is bad and spikes killing the points. So if the points look burned I would check that the wires are not just old an bad.

Contact Steve at B&B and change it over to negative ground and get a Petronix electronic ignition with a Flamethrower coil.

It has a new coil in it; I'll find the old one. 

TSC ign. kit came with a new condenser.  It's got a red insulator in the end as opposed to the old black one (different design). 

I have tried a jumper wire from the batt straight to the coil to rule out ignition switch.

Drained the carb - fuel was perfect.  I run 100% gas except when I know I can run a full tank thru in less than a month or so - try to limit E10 use in it.

I like the negative ground and electronic ignition idea, just want to rule everything else out.  Steve's plug wires are nice.

As far as that little plastic block in the side of the distributor - where can I get one of them dudes?  It appears to be OK, but I'm all about swapping everything minor.

Thanks for the suggestions... will keep looking.

Just to be on the safe side - check me on this:  to gap the points, I'm bumping the motor with the starter till the points are wide open - on top of the lobe in the distributor, then loosening the keeping screw, adjusting the brass screw until they lightly grab the 0.022 feeler gauge - the 0.024 won't go, the 0.022 will - this correct?  (They are supplied with a 0.020 gauge but the book says 0.022.)

Thanks again...


Edited by cbuttre835 - 19 May 2016 at 9:10pm

You have me wondering if the surface the points ride on to generate the gap is warn down too much. Also check that the advance springs in the distrubitor are working.

I have a Studebaker that ended up needing a tow as the little wire inside the distributor (between the points and the plastic block) started grounding out. That one will drive you nuts if it happens.... I changed nearly everything before I figured it out. All it ended up being was the insulation around that wire cracked off and it started arcing there.