B&S OHV engine turns but won't start.

I added fuel, added oil, cleaned the air filter and pre-filter and engine won't start. Engine turns but never starts. Removed one of the spark plugs to check it and then put a spark tester on the wire to check for spark. The other spark plug was still installed. I turned the key and the mower started up. Re-installed spark plug and mower won't start. Did the same thing with the other spark plug and again mower started with just one spark plug installed. I'm assuming if mower started I have fuel, air, and spark. Can someone point me in the right direction. It ran fine last december. Any help would be appreciated. Thanks.

 

It sounds like something is grounding out the ignition when both plugs are installed. If it only happened with one cylinder I could understand but if you can do your test on either cylinder and it runs on the other then it's got me stumped other than something with the ignition.

Long ago I did have a misfire problem with a JD LX188 with a Kawasaki engine. One plug would seem to go bad, I'd replace it and a couple weeks later the other plug would seem to go bad. Finally I replaced both plugs at the same time and it somehow solved the problem. Never did learn what was going on but it seemed to have worked.

 

Well I let the mower sit there for awhile as I did some other things around the house. Before I moved it back into the garage I decided to give it one more try. Mower started right up. I still have no idea what the cause or the fix was. I will find out if it starts tomorrow morning. Thanks PilotDane for the response. I may go ahead and buy some new plugs. Probably due to be changed anyway. Thanks again.

 

So, does it mostly have the problem when the engine is hot?

 

Here we go again. Same issue with mower not starting.

 

Well Pilot Dane, I did what you said, I replaced both spark plugs and charged the battery since I drained it while trying to get it running. Mower started back up. I'm really at a loss, and only hope it starts just fine next weekend. I will keep trying to start it everyday to see how it works.

I already had my eyes on a 24hp Husqvarna with a Kohler engine. I may still go ahead and get it and sell this one. This Troybilt is 11-12 years old, I think I've got my moneys worth out of it.

Wish me luck. Thanks again.

 

Could it be a problem in the kill circuit grounding it but you somehow disturb it when doing the plug changes? Try disconnecting the kill wire and see if it starts ok. Stopping it will then be the issue . choking it should stop it if it starts. Or isolate the disconnected kill wire with a jumper that you can easily touch to ground.