The Walden Effect: Farming, simple living, permaculture, and invention.

Back up generator update

Fouled spark plug of a medium sized generator


We had a power outage last night. It started around midnight and lasted till about 9 am.

The last time we used our back up generator was over 2 years ago, and I forgot to run all the fuel out of it when we were finished which created a situation where the engine would begin to start and then quit.
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It just so happens we were asking our helper Bradley about this problem last week and his advice was to drain the fuel and replace the spark plug which most likely got fouled up due to my neglect.

I almost got up in the middle of the night to see if I could extract the old plug and maybe swap it with one from the lawn mower due to the high temperature, but felt like it would go better in the light of day. Funny how the power came back on just as I got the old plug removed this morning. With any luck we'll remember to pick up a fresh spark plug tomorrow so we can be ready if the power goes out again.



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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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If the plug in only fouled with carbon like it seems to be in this case, just clean it with a steel wire brush and adjust the spark gap if necessary.

You can read the spark plug color to see what it wrong with the engine. AFAICT on the picture it looks like carbon fouling. Since carbon conducts electricity, this can short out the plug. You could use a multimeter to check the resistance of the plug.

Comment by Roland_Smith Mon Jul 2 17:16:32 2012
It could also be that the carburetor is gummed up and needs cleaning. With a little luck, replacing the gasoline with clean fuel with a bit of engine cleaner additive will do the trick. Otherwise you might have to disassemble it and clean the parts.
Comment by Roland_Smith Mon Jul 2 17:21:51 2012
Hey Y'all, You might consider running your generator periodically to keep it in ready condition. Our friends with whole house generators have theirs programmed to run for a few minutes once a week.
Comment by Cookie Mon Jul 2 17:23:59 2012

When you need a generator, you usually need it right away. To prevent "ethanol poisoning" and other issues, I run my generator for 10 minutes once a month. I only buy ethanol-free gasoline and put Stabil (gas stabilizer) in the can when I fill up. I also rotate my gasoline. I have multiple cans and once a month I dump one into my car or truck and fill it with fresh fuel and Stabil.
Following a routine like this, I always have a generator that will crank and fresh fuel to run it. While I'm running the generator, I also crank up chainsaws, mowers, tillers, weedeaters, etc. The army calls this PMCS (preventative maintenance checks and services). Semper Paratus!

Comment by David Hicks Mon Jul 2 18:00:37 2012

Roland-Now that you mention it I'll bet you're right about the plug only needing the carbon brushed off. Might use a piece of sand paper to get the under portion of the tip, should only take a few minutes to try. Thanks also for the suggestion of adding some fuel additive. I've got a can of Seafoam on hand for that and meant to write about it in the post.

Cookie-A regular system like what you described makes perfect sense. I'm thinking of getting a kit that will allow us to convert the generator to use propane which I think would help to decrease the problems with gasoline.

David-We had a similar system in the Navy but if memory serves me right we only called it PMS. I didn't know how important ethanol free gas is when I first started using this generator, but I'm with you on keeping the ethanol out of any system you might need to rely on in hard times. I've heard other people talk about Stabil, but have not yet tried it.

Comment by mark Mon Jul 2 18:27:42 2012

I wouldn't take the sandpaper under the ground wire or on the tip. Those edges need to be sharp to make a good spark, scratching them will not be good for it. Wire brush around the outside and you should be fine. At most take some carb cleaner (NOT wd40) and clean the tip out if you must.

I actually have that exact same generator. My suspicion is that you have the same problem I had with it. Just a little bit of debris or water in the carb bowl. Drop the bowl off of the carburetor and clean it out. That will likely get you going just fine.

The ethanol in the fuel has a terrible tendency to absorb water and it will collect in the carb bowl and the bottom of the fuel tank. Unfortunately, the only way to get the water out is to dump the fuel.

Comment by Andrew Mon Jul 2 20:27:17 2012
Andrew --- More excellent advice! You all are going to have Mark's generator humming in no time. :-)
Comment by anna Tue Jul 3 07:23:44 2012





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