JD 285 ignition problem

[Rob Laughton]

Hello.
I have a 285 lawn tractor with the Kawi FD590 engine.
It suddenly developed running problems.
I was in the middle of some restoration, painting, and tuning, so I thought I'd cleaned the carb wrong or something.
After much searching, it seems the igniter module may be at fault.
But I still have both sparks.
The engine will run briefly and very poorly, coughing and back firing out the intake.
I have spark at both plugs.
Fuel pump working.
I have 12 volts to the igniter, and a good ground
I tried to check for AC voltage from the pulsar coils and I got .3 volts from both. Someone here said it should be 15 volts.
I found an igniter test grid, that shows what the resistance should be between contacts, but the test is for a 425, so not sure if it's the same.
Before I spend $300 on a new igniter, could there be another reason?
It seems like the timing is off.
I took the rocker covers off and verfied the cams are turning. Is it possible to have the plastic cam gear break off one tooth, and upset the ignition timing?
All the other threads on igniter failures have no spark or only 1 spark.
I can do a video if it helps.
Any advice most welcome, thanks,
Rob

 

[Rob Laughton]

I forgot to add that I cleaning the original carb several times, and then bought a new one as well. The tractor behaved the same no matter what carb was there.
Rob

 

[RandyT]

Could be a loose or poor ground connections some place. Also how are you checking for spark. Using a spark type tester or just putting the spark plug on the head area and observing the spark. Grounding the spark plug to the head can give false readings. Heck even the blink type testers can give false positives on faulty plugs.

 

[Rob Laughton]

Thank you Randy.
I tested for spark both ways.
I'll check grounds again. For sure the ground in the wiring bundle from the igniter is good.
I'll try new plugs too
Rob

 

[Tinhack]

Sounds like valve or timing problem.
1. Make sure you have the coil(s) mounted correctly.
2. Make sure the cam is timed correctly.
3. Make sure the valves are adjusted correctly.

Forgot to mention: If you replaced the coils with new ones, the new ones may be wound backwards and have to be reversed--Flipped.

 

[Zebrafive]

The spec for pulsar output is 0.1 to 1.0 VAC

 

[Richard001]

Rob,
Can you describe exactly what you did doing this:

I was in the middle of some restoration, painting, and tuning, so I thought I'd cleaned the carb wrong or something.

As you said, the tractor was running good before your restoration.

Richard

 

[Rob Laughton]

Well, I'm embarrassed! It was bad plugs!
I've never had any trouble with 4 stroke plugs; just clean 'em and they work. And they were working before I did other work on the tractor.
Even though they sparked when held to the head, and with the tester, they didn't under compression. Randy said it.
That sure was a run around for me, although I learned stuff and have a better understanding of the tractor.
I'll provide links to 2 videos on Vimeo. The first long one I did to demonstrate the bad running. I'd just put new plugs in, and...wait, it started pretty good although very rich. So I figured the plugs were the problem, but the aftermarket carb was way off.
I put the OEM carb back on and my baby's back!
The second video shows it happy.
I'll post these in case someone finds it useful in future.
Thanks for pushing me a bit more, I was getting fed up and ready to buy an igniter.
I think the tractor just had a little Covid and is better now.
Cheers,
Rob
IMG_3751 on Vimeo
IMG_3761 on Vimeo

 

[Richard001]

Glad to see that you have got it sorted out. Good job.