Mower won't start. Possibly the ignition coil?

[Carl_1]

Hi, I have what I believe to be a 3.5hp Briggs & Stratton style engine, not sure on model as it was a supermarket branded mower. I have drained and filled with fresh fuel and oil, replaced spark plug and cleaned out carb with carb cleaner. I am getting no spark from the spark plug with a reading of 2.1k ohms when testing between the plug end and the body of the coil. I have also used the business card method to ensure correct spacing between the coil and flywheel. Is the coil in need of replacement?

Any advice or suggestions would be appreciated.

 

[BlazNT]

All engines have model numbers no matter where they are purchased from. That being said all we can give is general help without model number. Kill wire connected to coil needs to be disconnected to test if the safety switches are the problem or the coil.

 

[Carl_1]

Thanks, I will check later and see if there is a model/serial number anywhere. I can confirm that I removed the coil + spark plug and the kill switch wire before testing.

 

[BlazNT]

Kill wire to be removed for spark testing.

 

[Carl_1]

Yes I've removed the kill wire, grounded the tip of the spark plug spinning the flywheel by hand and still no spark. I am pretty sure it's the coil but thought I may have missed something. I know the resistance measurement of 2.1k ohms was just below what is said to be acceptable which I believe is 2.5-5k ohms. But I'm guessing this varies depending on which coil and motor ect... I know very little about lawn mowers and have only been doing some research the last couple of days.

 

[pugaltitude]

Does your coil have a metal spark plug cap?

If it does then pull it off (its a press fit connector and might take some force but don't try and pull the terminal off which its connected too) and connect the other end to the plug which is a tight fit and try and start.

Briggs don't give out ohms readings and only give a simple spark or no spark.

You should also be using a spark tester which loads the coil as if its under load from the engine.

 

[Carl_1]

This is a pic of the coil. Do you mean pull off the rubber angled plug to expose the metal terminal inside and then connect spark plug and try? I know I should be using a spark plug tester but this is only a cheap lawn mower and not worth wasting too much money just to diagnose problem. I have already changed the cheapest items i.e oil, fuel, spark plug. Will be better off buying a new/used one. Was just hoping this might be a quick fix.

 

[pugaltitude]

No dont pull it off as its not got a metal cap.
Model,type and code off engine would help.

Its very unusual for a coil to fail and a spark tester would diagnose easier.

 

[Carl_1]

I've looked over the engine and can't see any ID plate/model or serial number anywhere. Here is a pic of the mower.

 

[Carl_1]

Is this what you're talking about?