Couple questions, I recently purchased a used John Deere 180c greensmower. It was serviced prior to me purchasing it and the spark plug was new among other things. In a case of bad judgement, I ran some old gas in it to get rid of it so I could refill my gas can with fresh gas. As I was cutting, it died while it was idling emptying the grass catcher and I couldn't get it to crank again. I finally pulled the spark plug and it was completely black. I was able to scrape the contact point with a wire brush and it fired right back up after that. My question is, could that have been caused by the old gas or do I have a bigger problem? Is there a way to adjust the mixture on the carb like you can do with a car if it is running rich or lean, etc? Any help is much appreciated!
SSE Dad
Some Carbs are indeed adjustable, others have anti-tamper devices that while annoying, are usually bypass-able.
Old gas can certainly foul a plug but it would have to be pretty rank to do so.
I would not make major adjustments until it's running on good clean fuel and the carb is known to be in good condition/clean.
Old gas can certainly foul a plug but it would have to be pretty rank to do so.
I would not make major adjustments until it's running on good clean fuel and the carb is known to be in good condition/clean.
I have this same problem with my 180b. I have to swap plugs every 2-3 weeks. I have a few extra that I keep in rotation and ready to go. It hasn't been a big deal. I also use recreational fuel with high octane which I think might be my problem. Going to try regular soon. If not, going to order a new carb.
Id be skeptical that bad gas could or would foul a plug. I would say that the carbon you saw was more likely a result of it dying and you not being able to get it to crank again. If you crank and crank and crank the engine and it wont start, it can absolutely foul a plug because youre dumping fuel into the engine but there is no ignition to burn the fuel away, so it can sometimes foul the plug.
Especially with a 4-cycle engine, you can easily foul the plug that way.
Especially with a 4-cycle engine, you can easily foul the plug that way.
In my situation, I've pulled a plug with only 20 minutes of run time and it's been BLACK. I definitely have a carb problem (although I cleaned and rebuilt it), or the high octane rec fuel isn't working well with the current setup.
I don't own a mower like that but I had a few thoughts that maybe could help. When you say the plug was black, what do you mean? Was it wet and shiny black? Or was it dry/dusty black? Sounds more like it was carbon build up based on being able to scrape the electrode off and start it again. If thats the case then its running rich, which I would see as more of a carb issue than anything else. In my experience bad gas will cause problems pretty quickly when using it, so with a small tank like on a mower I would imagine you would have had problems before you had to empty the grass catcher.
It was more dry/dusty black. The other poster made a good point about me maybe trying to crank it so many times too and that producing a carbon build up. I bought a new spark plug I'm going to run the next time I mow and see how she does. If that doesn't fix it, I guess I'll be looking into adjusting the carb if possible or replacing it altogether.Midsoutherner said:
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