Help Please with No Spark to Plug but starter turns over

Todd Renaud

With my Senior FR125, the starter will turn over when the starter button is engaged but no spark gets to the plug.

Right now, I don't have any extra spare parts to try and swap out so before I go buying/searching for some, any suggestions on what I can test with a test light or voltmeter to at least see where the "spark" gets to before it disappears.

We originally didn't have the harness connected properly as the starter wouldn't even turn over. That's why I feel it COULD be something with our connections and not necessarily a failed part.

Also, what triggers the coil so that it will fire the plug?

TIA...Todd

Matthew Chin · Joined: 09 Sep 2009 Posts: 31

There is a small crank angle sensor (or something similar) on the backside of the engine that has a 2 prong plug that goes to it to determine when to send the spark. It is under the exhaust closer to the drivers seat. Make sure that it is plugged in and is not loose.

Todd Renaud · Posted: Wed Jun 06, 2012 12:43 pm Post subject:

Curtis Cooksey · Advertiser Joined: 16 Aug 2001 Posts: 311

Mistake
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Todd Renaud · Posted: Wed Jun 06, 2012 2:55 pm Post subject: Re: become one

Matthew Chin · Joined: 09 Sep 2009 Posts: 31

is your grounding strap good?

russ jolly · Joined: 09 Dec 2010 Posts: 3

Pull your plug leave it in the boot and let it rest on the head. turn it over. if no spark try pulling the boot and reconnecting it, sometimes they get loose. If that doesnt work get a volt meter and test the volts going to the coil,...

Bruce Woodrow · Posted: Thu Jun 07, 2012 11:21 pm Post subject:

Since you know the battery is OK (engine turns), there are only 5 items in the system to check:

1. Ignition switch - you can check this with a test light or voltmeter
2. Crankshaft sensor - never heard of one causing a problem unless physically damaged
3. Ignition coil assembly - only easy way to check is by replacement
4. Main wiring harness - after checking ignition switch, disconnect the coil connector, switch on ignition switch and make sure there is a 12v feed at one of the terminals.
5. Engine/coil grounding - the grounding eyelet on the main harness should be attached to the engine casing (usually using one of the coil mount studs) AND the coil casing and engine casing must be connected by 1, or preferably 2, grounding wires (again using the coil mount studs)

Hope this helps,

Bruce