Robin Subaru 10hp- no spark after hard ride

[Chupacabra]

Here is what the symptoms are-

Went on a bumpy ride last weekend. The Kart has a keyed (electric starter) ignition and a secondary shut off switch. When I arrived back home I tried to shut it off with the switch, and nothing happened, then I turned off the key and the switch again and it still kept running till I finally found the combination of key and switch that shut the engine down. It was all backwards and I also noticed that I didnt have lights either. It wouldnt start back up...hmmmm

So I pushed it into the shop and took off the battery cover and found what seemed to be the problem. The ground wires on the battery had snapped off at the terminal. easy fix right? I bought a new cable end for the ground cable to the motor, and a new end to the smaller 16 gauge wire for the lights. whala...I have lights but no spark at the plug.

I dont know how long I was driving around with the ground disconnected but I know it must have happened while I was riding...the buggy never shut off though (until I got home and had to flip all the switches in backwards order to get it to turn off. It had to be over the span of about 15 minutes.

Could I have fried the coil with the ground being not connected? The magnetic plate on the flywheel also looks weird too. It is "stepped" and looks ground down. The two screws that hold it to the flywheel look like they were ground flat and you can barely see the star-phillips pattern in the top of them. The plate itself looks like it was rabbited on the side closest to the engine...just did not look right. (ill try to get some pics posted of this)

what do you think could have happened to the electrical system to now not have any spark after those circumstances?

....and on top of all that the SOB is not getting gas either...dry plug when I turn it over. Going to clean the carb today, however wanted to solve the spark issue as well.

Let me know if any of you electrical gurus can help.

 

[r97]

my first two thought were that some electrical connections came loose, or maybe some oil got in the cylinder and fouled the plug. pics will help sort out the problem.

 

[anderkart]

Most engines like yours have a 1 small wire running from the magneto that's connected to a kill switch (or to both an ignition sw. and kill sw. in your case). Normally the engine will get spark and run with this wire completely disconnected, the switches simply ground this wire to kill spark. I'm getting the feeling one of your kill switches is defective and now supplying ground all the time in any position.

The first thing I'd try on yours is to disconnect all wires from your kill switch and recheck for spark.

If that doesn't help, make sure the wire running to that switch isn't pinched/crushed/shorted to the frame somewhere and picking up its ground source from there.

Still no spark: Try to locate and disconnect this wire from your engine or key switch.

Not sure about your flywheel/"magnetic plate" issue but that might be your spark problem so definitely post some pics. Might as well make sure your flywheel retaining nut isn't loose and also try pushing/pulling the flywheel in and out to check for excessive crank shaft end play.

Maybe your still getting fuel, spark plugs dont always look wet in situations like this.

 

[Chupacabra]

Here are some pics of the magneto and the magnet on the flywheel. just did not look right to me. Is the metal on the magneto supposed to touch the magnet on the flywheel?

If it does, then there is a problem. The metal clears the flywheel by about 1mm (the depth of the groove cut on the metal plate)

The weird thing is that just the screw heads are shiny like they were ground down....the metal looks the same.

The ends of the magneto look like they have never been scraped either.

Take a look and let me know what you think.

The flywheel is on good and tight. I will need a flywheel puller to get it off for sure.

 

[Doc Sprocket]

I'm unsure about your particular engine, but every time I've set up a small engine mag, I've used a standard business card to set the distance between the magnet and the laminations. I think it's about .020". Looks to me like your gap's too big.

It also looks like the visible damage may have been caused in the past. Maybe the coil came loose and caused it, and the PO fixed it. You didn't say if you had owned the engine since new. Look up the specs for your coil and test it with an ohmmeter. It may still be good, in which case, just re-set it with the approprate gap.

 

[Chupacabra]

I've have not had it since new...I think its had a few previous owners. The big question that is buggin me is how it happened. The cart was running fine then all of a sudden...nothing.

We I have some good advice from everyone above. I will check out the gap and see if I can set it down a little. It may be old damage but I am thinking about pricing out a new flywheel and magneto anyway.

I will try the grounding vs non grounding tomorrow.

Do you think its a possibility that my keyed switch is acting up also? When I turn the key the starter cranks right up...could it do that and still not be providing spark to the flywheel?

 

[Doc Sprocket]

Do you think its a possibility that my keyed switch is acting up also? When I turn the key the starter cranks right up...could it do that and still not be providing spark to the flywheel?

It's possible. It's also possible that the kill switch circuit (previously mentioned) has a fault. Starter would still operate as normal, but not spark. unplug the kill wire right at the engine block and try to start it.

 

[r97]

i would suggest you just do simple things first. carefully look over all you wires, make sure all connections are good, and test every witch and wire (some times the damage cannot be seen). if everything checks out good, test your spark plug, find another engine and remove spark plug from the kart engine, then put the kart engine spark plug into the other engines spark plug wire, ground the hexagonal part of the spark plug the the engines frame and pull the starter, if you get a spark, good, if not, buy a new plug. take a working spark plug and attach the kart engine spark plug wire to it, ground the hexagonal part of the plug to the engine, and pull the cord, if you don't get a spark (again this is with all other electrical checked, using a good plug, and with the key in the run position) try re-adjusting the gap on your magneto (everything looks mighty rusty, make sure the fly wheel magnet is still magnetic, it should be pretty powerful). then re try the magneto test, if its still no good i would suggest repeating all of the above before spending money on a new magneto.

 

[Chupacabra]

the flywheel is not that rusty. Its just non painted metal so it oxidizes over time. No flakey stuff at all. I have cleaned it real well with some pb blaster and it looks like its new/old self again (gray color). The engine is a 2004 Subaru Robin 10hp.

I need to get this sorted today. I took a half day off of work to do it. I work from home so it works out even better.

I will ley you all know the results tonight.

 

[Chupacabra]

well that didnt take long.

What I did was take off all of the battery leads and disconnected that part out of the equation. It has a pull start on it so thats the down and dirty way to start it. (Keyed ignition spoils you).

So I set the gap and unhooked the ground lead on the ignition coil. Took a fresh plug and put it in the boot. no spark.

Do deducing this way, is it now possible that my coil went bad during last weekends mayhem? Like i mentioned..it was running fine until I got home and shut it off. Refer to my first post with the electrical on off switches and keyed were acting up when I went to turn it off.

Thoughts? I have a an Ex27 manual for the engine with parts list. I guess I can just call and give them the product number for my engine and tell them what I need.

If I am going to replace the ignition coil, do you think its wise to replace the flywheel as well?

 

[Doc Sprocket]

As long as you can set the gap properly, the flywheel should be fine. Others may disagree.

Unhooked the ground lead? That's needed! (Unless you mean the one that goes to the kill circuit)

 

[anderkart]

Took a fresh plug and put it in the boot. no spark.

You grounded the threaded portion of that spark plug... right?

 

[r97]

just follow what i wrote and you can trace the electrical problem, then fix it!
http://www.harborfreight.com/automotive-motorcycle/diagnostics/6-12-volt-circuit-tester-4288.html

 

[Chupacabra]

You grounded the threaded portion of that spark plug... right?

yes...I grounded the plug to the engine. I did unhook the ground wire for the on/off switch

 

[anderkart]

If you have access to an ohm meter/multi-meter you could take some test readings between ground and the end of your spark plug wire.

Also take a reading between ground and your magneto kill switch wire while its unplugged from your switches.

I dont know what the exact specs should be but I'd guess if you get a reading of open/infinity (0.000) or a dead short (0) with either of these test, you'd be confirming a defective magneto.

ps: if you get a infinity reading through your plug wire test (and the plug wire is permanently attached to the mag) you could push a small needle into the center of the plug wire right where it exits the magneto, and then retest to confirm that the plug wire itself isn't just defective.

 

[Chupacabra]

well it too late for testing the ignition coil and plug wire...I already purchased a new one from Northern Tool. I hope to pick it up today. I was kinda surprised that it cost 90 bucks...the flywheel cost 190 plus tax and shipping. I held off on that purchase, however.
I guess Robin Subaru really thinks their stuff is good for those kind of prices.

 

[mogyver69]

well it too late for testing the ignition coil and plug wire...I already purchased a new one from Northern Tool. I hope to pick it up today. I was kinda surprised that it cost 90 bucks...the flywheel cost 190 plus tax and shipping. I held off on that purchase, however.
I guess Robin Subaru really thinks their stuff is good for those kind of prices.

I know this post is a bit old but did you ever figure out the no spark issue. I have the same cart with the same problem.... No spark....I eplaced the coil and still no spark. I ohmed tested the stator and it doesnt appear to have any shorts to ground and it has continutity between the two wire... Im thinking the flywheel is the issue. Is that magnet on the top were the screws look sheered off a diode of some sort?

 

[mogyver69]

I've have not had it since new...I think its had a few previous owners. The big question that is buggin me is how it happened. The cart was running fine then all of a sudden...nothing.

We I have some good advice from everyone above. I will check out the gap and see if I can set it down a little. It may be old damage but I am thinking about pricing out a new flywheel and magneto anyway.

I will try the grounding vs non grounding tomorrow.

Do you think its a possibility that my keyed switch is acting up also? When I turn the key the starter cranks right up...could it do that and still not be providing spark to the flywheel?

My flywheel looks exactly like yours and im dealing with the same issue no spark... I beleive though that the grove there is considered normal. Theres a step there for the coil to clear and I dont thing the sensor there on the flywheel is replaceable... You have to replace the whole flywheel.... Im still researching myself. I replaced my ignition coil but still no spark... If you have fixed your Kart maybe you could help me with what youve learned... We have the same engine....

 

[Bluethunder3320]

My flywheel looks exactly like yours and im dealing with the same issue no spark... I beleive though that the grove there is considered normal. Theres a step there for the coil to clear and I dont thing the sensor there on the flywheel is replaceable... You have to replace the whole flywheel.... Im still researching myself. I replaced my ignition coil but still no spark... If you have fixed your Kart maybe you could help me with what youve learned... We have the same engine....

gap the coil to the flywheel correctly (look up specs). sand the magnet on the flywheel if its rusted. disconnect the kill wire(s) from the coil and pull start to check spark with a correctly gapped plug. also a good plug.

thats all i can think of that would cause a problem

 

[mogyver69]

gap the coil to the flywheel correctly (look up specs). sand the magnet on the flywheel if its rusted. disconnect the kill wire(s) from the coil and pull start to check spark with a correctly gapped plug. also a good plug.

thats all i can think of that would cause a problem

Ya I did all that.... The go kart has been garaged all its like so its very clean but I did clean the flywheel with 220 wet sand paper to clean any rust.. I gapped the air gap to .3 mm as it says in the manual....And I replaced the spark plug with the ngk replacement.
WHats strange to me is what gives the coil power to spark? theres the charge coil which is under the flywheel. It has to create power which runs thru the flywheel Im assuming to give the coil power to spark?

Thanks for your help......