No spark at plug
- Thread starter stonum
- Start date
To add to my fun, my alternator in my car went out this morning. So now, I'm trying to deal with 2 things at once. Plus, it's raining and cold and dark here. Anyway, here's some pics of my mower. It needs a washing, but it's just too nice a mower to give up on. I put on new belts and tires and battery, and fuel filter, ect... just 2 years ago. It's run so well up till now.
ILENGINE
Lawn Royalty
That is the Digital Spark Advance Module or DSAM for short. It controls spark timing and advancement. When it fails can cause a no spark issue. When doing the DSAI conversion that box can be removed and tossed in the trash because the conversion doesn't use it.
I threw a new alternator in the car Friday, so now I can start looking closer at my mower, using the info you all have provided. Or I can go to Home Depot and buy a Murray MT 100 42 in. 13.5 HP for $1700, which isn't in my budget at all. Everything on my Craftsman works so good, I just got to get that plug sparking. Trying to cut my big lawn with my walk-behind is a major pain.
I would check the air gap
VegetiveSteam
Well-Known Member
CV16 engines with no spark issues are mostly unheard of except on Craftsman mowers. On Craftsman mowers it was fairly common. The issue was normally a bad equipment relay. There are typically 3 relays somewhere under the hood. One of those has most likely failed.
I don't remember whether the relay was wired into the ignition kill circuit or if it provided power to the Spark Advance Module. If it were wired to the kill circuit, it's job would be to unground the white kill wire from the Spark Advance Module. If it's wired in the power circuit, it would provide battery voltage to the Spark Advance Module.
Simply check the red wire going to the Spark Advance Module for battery voltage with the key in the on/run position and also while cranking the engine. If you have power, disconnect the white kill wire from the Spark Advance Module and see if spark comes back.
Could it be a Spark Advance Module or ignition module issue? Sure, but the failed relay was a much more common issue. And unfortunately, you can't just move the relays from one position to another. All 3 have to be working.
I don't remember whether the relay was wired into the ignition kill circuit or if it provided power to the Spark Advance Module. If it were wired to the kill circuit, it's job would be to unground the white kill wire from the Spark Advance Module. If it's wired in the power circuit, it would provide battery voltage to the Spark Advance Module.
Simply check the red wire going to the Spark Advance Module for battery voltage with the key in the on/run position and also while cranking the engine. If you have power, disconnect the white kill wire from the Spark Advance Module and see if spark comes back.
Could it be a Spark Advance Module or ignition module issue? Sure, but the failed relay was a much more common issue. And unfortunately, you can't just move the relays from one position to another. All 3 have to be working.
VegetiveSteam
Well-Known Member
This is from the Sear parts website. You can probably get a relay at a local parts store. Just make sure the terminals and in the same configuration and have the same numbers on each terminal.
I tried your suggestion. The voltage is there with ignition on and cranking. No spark at plug with white wire disconnected. I got a feeling this is going to take a while to figure out.
Also, here's those 3 relays.
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My next thing to try I think is to get new relays. I'm trying not to just give up on this mower, but it ran like a brand new one up till now.