2003 DS intermittent no start

[raggdoll]

Not sure why, this cart has been completely gone over and super well maintained.

Every now and then, when cold, no start. Check spark. None.

Turn it over and try again every 5 or so minutes, then after 4 or 5 try's it magically has spark.

I'm at a loss here, any ideas?

[Fairtax4me]

Could be a failing lower microswitch switch on the throttle cam. Testing it might be inconclusive if it's an intermittent problem, especially if it doesn't do that every time.
Pull the white/black stripe wire off and see if the problem persists. If that fixes it replace the switch.

[CP241]

Could be a bad coil too. The FE350 I just dropped in my DS was doing the exact same thing. Sometimes nice spark ran great. Sometimes a faint yellow spark, if I could get it to spark at all. This time, I caught it in a failed state and put a meter on it, had 13k ohms through the secondary coil (spec is around 8, and another 5k through the plug cap), but 2.something MEGAohms (basically no continuity) through the primary coil, which spec is around 1 ohms. Swapped it with a spare coil from another motor I have apart that tested in spec, and nice fat blue spark.

Funny thing is, I dropped the bad one on the floor a couple times, and suddenly it tested correct per spec.

Luckily I thought ahead... Before I put this engine in the cart I intentionally removed the 2 bottom 10mm bolts on the fan shroud... just in case. So I was able to swap the coil relatively easily without pulling the motor. It still fought me a bit, but less so than pulling the motor out

[raggdoll]

Originally Posted by Fairtax4me

Could be a failing lower microswitch switch on the throttle cam. Testing it might be inconclusive if it's an intermittent problem, especially if it doesn't do that every time.
Pull the white/black stripe wire off and see if the problem persists. If that fixes it replace the switch.

Will do!

Originally Posted by CP241

Could be a bad coil too. The FE350 I just dropped in my DS was doing the exact same thing. Sometimes nice spark ran great. Sometimes a faint yellow spark, if I could get it to spark at all. This time, I caught it in a failed state and put a meter on it, had 13k ohms through the secondary coil (spec is around 8, and another 5k through the plug cap), but 2.something MEGAohms (basically no continuity) through the primary coil, which spec is around 1 ohms. Swapped it with a spare coil from another motor I have apart that tested in spec, and nice fat blue spark.

Funny thing is, I dropped the bad one on the floor a couple times, and suddenly it tested correct per spec.

Luckily I thought ahead... Before I put this engine in the cart I intentionally removed the 2 bottom 10mm bolts on the fan shroud... just in case. So I was able to swap the coil relatively easily without pulling the motor. It still fought me a bit, but less so than pulling the motor out

I hope its not the coil, I heard its a bitch to change.

[CP241]

Theres not a lot to the circuit. So as FT4M said, unplug the bullet connector next to the rev limiter. If spark is good, then it's a microswitch problem. If not plug it back in, that ain't it. Disconnect the rev limiter ground wire. If spark is good, rev limiter is bad. If not, plug it back in. Only thing left would be the coil.

I replaced mine the other night in about an hour, but theres no body on my DS and I intentionally removed the 2 bottom fan shroud bolts before I installed the motor. If those bolts are in, I dont think you're going to get to the coil to replace it or gap it without pulling the motor out.

[raggdoll]

Originally Posted by CP241

Theres not a lot to the circuit. So as FT4M said, unplug the bullet connector next to the rev limiter. If spark is good, then it's a microswitch problem. If not plug it back in, that ain't it. Disconnect the rev limiter ground wire. If spark is good, rev limiter is bad. If not, plug it back in. Only thing left would be the coil.

I replaced mine the other night in about an hour, but theres no body on my DS and I intentionally removed the 2 bottom fan shroud bolts before I installed the motor. If those bolts are in, I dont think you're going to get to the coil to replace it or gap it without pulling the motor out.

Great info. Thanks

[raggdoll]

Originally Posted by CP241

Theres not a lot to the circuit. So as FT4M said, unplug the bullet connector next to the rev limiter. If spark is good, then it's a microswitch problem. If not plug it back in, that ain't it. Disconnect the rev limiter ground wire. If spark is good, rev limiter is bad. If not, plug it back in. Only thing left would be the coil.

I replaced mine the other night in about an hour, but theres no body on my DS and I intentionally removed the 2 bottom fan shroud bolts before I installed the motor. If those bolts are in, I dont think you're going to get to the coil to replace it or gap it without pulling the motor out.

So no start again this morning. Pulled the brown rev limiter ground and it started :)

So must be a bad rev limiter right? Why would it work sometimes and not others, ie: intermittent no starts?

[CP241]

It's not uncommon for electronic comoonents to fail intermittently before a hard failure occurs. This is across anything... cars, golf cart, computer, home electronics, anything really. Could be something as simple on component level as a leaking capacitor, cold solder joint on the PCB, etc.

As to exactly what fails inside these things, I dont know. I've never opened one up to see. Parts like this are usually filled.with an epoxy resin for weatherproofing and kind of a PITA to remove it to access the components on the PCB to try and determine true root cause.

But, back to subject, I would tape up the eyelet to make sure it doesnt touch anything metal and drive it for a bit before replacing it. Just to make sure it's not a coincidence. Sometimes intermittent failures are the ones that drive you nuts.

[raggdoll]

Originally Posted by CP241

It's not uncommon for electronic comoonents to fail intermittently before a hard failure occurs. This is across anything... cars, golf cart, computer, home electronics, anything really. Could be something as simple on component level as a leaking capacitor, cold solder joint on the PCB, etc.

As to exactly what fails inside these things, I dont know. I've never opened one up to see. Parts like this are usually filled.with an epoxy resin for weatherproofing and kind of a PITA to remove it to access the components on the PCB to try and determine true root cause.

But, back to subject, I would tape up the eyelet to make sure it doesnt touch anything metal and drive it for a bit before replacing it. Just to make sure it's not a coincidence. Sometimes intermittent failures are the ones that drive you nuts.

I agree. Wiil do and thanks for your response!!!