Plugs on a 2 stroke when idling alot?

[z33tec]

So I've read that 2 strokes don't like to idle a lot and should be run close to WOT for a while to get the plugs hot and clean them off before ending your day. I don't always have the ability to do that where I normally launch my boat at, due to lack of room in the bay, or large waves on a windy day.

What do most people do for 2 strokes that have to idle a lot and aren't always run at WOT on every outing? Do you pro-actively replace your plugs a couple times a season, just so they don't foul up from getting too oily? Just curious what the best way is to handle it.

 

[Attwanl]

I had a small 2-stroke tiller 6 1/2 hp, I tested “ run wide open before you load up “ theory. We nick named it ( the other was too long), “ the after burner test”. I’ll shorten up the story to the reader’s digest version, new plugs went out normal outing. Run WOT before loading up. Almost perfect color little dark but I was satisfied.
Next trip new plugs normal outing DIDN’T run WOT before loading. Color of plugs not so good, not horrible, but still not good.
Third trip out I left plugs from outing 2 in and run WOT to a place we were going camping for the weekend. I pulled the plugs and they looked almost like the ones from outing 1 were I run WOT before loading up.
We were all standing around discussing “the after burner” results.... re-jetting , float levels, air intakes and everything you could do to cure it.
The quiet one in our group spoke up and said “ Why don’t we just carry an extra set of plugs and a wrench in the boat, and let’s go fishing”.
We still laugh about the “After burner test” today.

 

[Weldorthemagnificent]

I clean plugs with alcohol. Can use brake clean or acetone as well. Just swish them around in a jar then keep the spare set in a Ziploc in my tackle box along with a wrench. Then you can swap them out if needed.
You can also run the next hotter plug in the heat range. For example, my motor calls for j4c plugs. J6c is the next hotter plug and will burn off carbon a bit better. Regular seafoam treatment will also help keep things clean.

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[MrGiggles]

You don't necessarily need to replace them. You can keep a couple sets and burn them off with a propane torch, then rotate them.

With good quality oils at 50:1, I don't think it's as big of an issue as it used to be. Even less so with variable oil injection. It is mostly a problem while trolling and running at an idle for hours on end.

Even in my pre-mix motors, I never had an issue fouling plugs, but did rotate them every few months. Granted, I don't idle all that much either.

 

[z33tec]

Thanks for the feedback guys. I do like to clean off plugs if I know they aren't that old, but I did read that if oil soaks into the ceramic for a while they may look clean and good but still not work well. I'm no scientist, so who knows, might just be someone's "theory".

Sounds like best idea is to carry a spare set and maybe clean/rotate them every month or two ahead of schedule. Takes no time to do anyway.

For what its worth, I pre-mix 50:1 on a 1990 70hp Johnson, so maybe its bigger of an issue than those running VRO's or something.

 

[NautiBuoys]

I do extended trolling for stocked trout in my 35 HP Johnson and my OMC engine manual lists using a colder plug when extended trolling. No issues whatsoever and purrs like a kitten...

 

[GYPSY400]

I run good synthetic mercury oil at 60:1. Both my motors run like a top at idle and wot. I'd be tempted to run 100:1 if I was trolling all the time, but thats a little slim for me. I've never fouled a plug.

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[Pappy]

No need to do any of the above.
Extended idling puts an oily but soft film on the plugs. They are not fouling. That is a thing of the past. Heck I run my antique engines on a 16:1 oil ratio and have not fouled a plug in years.
As long as you are not adjusted too rich at idle they should idle all day long and come right up on plane and burn off the light film immediately. You guys are overthinking this!
Quite a few years ago a hotter plug was recommended for extended idle (not colder like was mentioned above) but that recommendation went away. With a good working thermostat the production plug is running in the range it was designed for.

 

[turbotodd]

pappy's right

and I'll reiterate that some folks just have to run rich oil mixtures and that seems to complicate things (and more than just plug fouling). Also, some aren't careful when mixing oil and gas, either lean or rich, they''ll pour in a little oil without knowing exactly how much fuel is in the container and call it good. How many engines have I seen burnt up because of improper or failure in mixing? Plenty. Fouling is a thing of the past and some of that is also part of the designs of more modern engines and carburetors and also fuel. Today's fuel is nothing like it used to be. Neither is oil.