No spark 1450 w/ K321 engine

[rkwilliams]

Long story, but last year I bought a pretty nice 1450. It smoked a bit, but otherwise ran fine. Had a goal to rebuild engine this past winter, but since we had virtually no winter here in NC, I didn't get to start on things until a month or so ago. Pulled the engine, and while at it decided on pretty much a complete tractor overhaul with new paint, decals other mechanicals, etc. Fortunately the engine bore and crank showed virtually no wear when disassembled, and I was able to go back with standard piston/rings, connecting rod. Now putting tractor back together, and before putting the engine back in the frame, I decided to crank it over to make sure I had spark at plug. There is none. New Kohler points and condenser. There was a lot of gunk around my alternator coils when I got flywheel off, but I cleaned all that up real good. Resistance reading was good. In fact, I bought a new coil, but since the resistance measure on old one and new one was the same, I kept the old one since it was official Kohler. New rectifier installed, and I'm pretty sure that all my connections are right. I went back with my same coil, but it was functioning fine before I started any of this.

So my basic question is this: is there something else involved in order for spark to happen when the starter is cranking the engine outside of full install on tractor? The only things I really can't account for are the two wires going to a plug that at present are not connected. This plug has one wire going to the center terminal on the rectifier and one to the + terminal on the coil...as shown in photo. What am I missing? And yes, that is a new 13-tooth starter. Old one had gotten sluggish and sometimes would not kick in at all. This one spins the flywheel great. Here's photo with the plug I refer to that ultimately goes to the ignition switch and battery/charging system.

I'll post final pics when all is said and done. This is my WORKING tractor, so the rebuild project hasn't been to make it a show piece. However, I want it to look good, be protected with decent paint job and other precautions and generally be good for another 50 years with routine maintenance.

 

[kmcconaughey]

With all that nice new paint, perhaps you're not getting a proper ground connection. I would verify that all the connections are good. If you have a Volt/Ohm meter, disconnect the battery and use the ohm meter to make sure the connections are good.

 

[rkwilliams]

I think my grounds are good to the point where I know to make them. The body of the condenser is grounded via the bolt into the block. I don't see where anything else requires a ground. There are those two wires on the connector that I circled. One goes to the center terminal on the rectifier (red wire) and one goes to the + terminal on the coil. The starter turns fast and strong, but when I watch the plug, no spark. So do those two wires in that connector need to be connected to something in order for me to get spark in this test situation?

 

[podenbach]

You had flywheel off, check air gap. Could be interrupting switch/diode

 

[snicklas]

How are you turning it over? By hand on the bench? Or is it installed in the tractor, and you are using the key?

If it's sitting the bench, and you don't have a battery connected, I don't think you will get a spark. I may be wrong, but these have a battery ignition. The magnets on the flywheel and the stator are essentially an alternator to charge the battery. That is not a magneto like some other engines have.

 

[jstich]

Yes, that circled connector is pretty important. It plugs into a matching connector that goes to the ignition switch to supply power to the coil.
I would highly suggest that you put the engine back into the tractor, because if you do get it running on the bench without the battery as a load for the charging system, you will most likely fry the regulator. Last one I had to buy was $60
If you really feel the need to see spark, connect 12 volts to the + terminal of the coil and crank it as you have been.

 

[etopel]

First, like Kraig said, check your grounds especially the condenser. Then check your points for clean contacts. even if they look good new points often have a film on them- clean them a little. Then you can hook up your battery positive to the coil and negative anywhere on the engine it can make good contact. Work the points with your finger, you should see a small spark at the points when they open. If that checks out go ahead and crank it over. The alternator system has nothing to do with the ignition, it just charges the battery. Don't leave power on the points to long sitting there, they can get burnt. Good luck.

 

[rkwilliams]

Thanks. My points are brand new and are true Kohler brand. Before installing (and then again after installing) I dragged some 400 grit wet/dry sandpaper between the contacts a couple of times. I think they should be clean and bare. To make it clear, I have no intent on starting the engine as it currently sits on my bench. I was just trying to be sure a spark was present before getting it back into the tractor. Would really prefer not to have to pull it back out again to disassemble and remove flywheel, for example. If I'm understanding correctly, the spark is purely a product of power from the battery and nothing to do with with the magnets' excitement. Now that I think about it, that makes sense. I'm more used to simple 1-cyl engines with a coil that has magnets on the flywheel pass by to generate the spark.

I'll give some of your suggestions a try and will report back.

 

[dschwandt]

Depending on Ser#, there should be a ground wire from one of the starter mount bolts to one of the grill mount bolts, or, from the righ6t side firewall mount bolts to the block where the clip that holds the wire harness going to the rectifier.

I have seen either way depending on whether or not the tractor had an aluminum or cast iron grill or the wire harness routed THROUGH the fire wall w/a grommet or alongside through a clip.

 

[danderson]

You have your rectifier installed wrong. I see you have it spaced off the blower housing so you can put the connector on. It backwards. The fins go into the blower housing to keep it cool. Just replaced one on a 317 John Deere because someone bolted it outside the housing and it overheated. This shows it on my 1250

 

[glippert]

Nice catch, Doug. I looked at the pic and didn't even notice.

 

[danderson]

I wondered why someone didn’t see it. Jumped out out at me. Probably because I just worked on one.

 

[bfleisch]

You have the points gapped correctly? Remove the points wire from the coil and use a meter, one lead on ground and the other the points wire and turn over by had and make sure you see it go from a short ( 0 ohms) to open ( infinity or OL depending on meter). That does not check for the correct gap, but it at least will rule out them being dirty and not operating.

 

[danderson]

While it’s on the bench static time it.
http://www.mgonitzke.net/cubcadet/tools/static_timing.pdf