Too rich?

[950speed]

As the title says, is this plug saying my mixture is too rich?! It’s an .038 main jet along with open header and high flow air filter

 

[Budget GoKart]

Mine might be too

 

[950speed]

Mine might be too

Yea I’m just not to sure, and don’t want to foul my plug or mess the engine up

 

[Ebrownie]

You’re just fine. In my opinion anyway. It might be a bit rich, but as long as it revs good and doesn’t sputter or ever lose power, it’s not a problem. You might foul a plug here and there, but rich is better than lean. But I know people will disagree with me on not worrying about it.

 

[Budget GoKart]

Well i rather my engine run lean aslong as it doesnt sputter

 

[itsid]

unfortunately that pic is not well enough lit to make a good call ..

But it's the insulator you should care about most, not the thread.
And that looks okay to me (again, can be deceived by the camera flash)

So I could say I'm with Ebrownie here if that pic is all we have to judge.

Then again, the rest looks pretty bad...
So while I wouldn't rejet just yet,
I think I'd adjust the idle closer to perfect and maybe lean out the main just a hair
(in case it's at all settable for your carb)

clean that plug as good as you can (wire brush, wash in fuel then scotch brite)
reinstall it;
drive; throttle up to max rev and keep there for about a minute,
cut the engine off and get another pic of the plug (outside bright sunlight)
on a white sheet of paper.

That way we have a much better pic to judge.

This is a good chart to compare to:


'sid

 

[J.S.@SMS]

Do they have one of those charts for X style plugs?

 

[950speed]

unfortunately that pic is not well enough lit to make a good call ..

But it's the insulator you should care about most, not the thread.
And that looks okay to me (again, can be deceived by the camera flash)

So I could say I'm with Ebrownie here if that pic is all we have to judge.

Then again, the rest looks pretty bad...
So while I wouldn't rejet just yet,
I think I'd adjust the idle closer to perfect and maybe lean out the main just a hair
(in case it's at all settable for your carb)

clean that plug as good as you can (wire brush, wash in fuel then scotch brite)
reinstall it;
drive; throttle up to max rev and keep there for about a minute,
cut the engine off and get another pic of the plug (outside bright sunlight)
on a white sheet of paper.

That way we have a much better pic to judge.

This is a good chart to compare to:
View attachment 106698

'sid

I will get a new picture here soon!

 

[Flyinhillbilly]

I’m agree that rich is better than lean. Judging by what I can see if it runs ok I wouldn’t mess with it. I run two race karts rich on the pilot circuit for better throttle response with no problems. I run my alcohol kart rich too. Too many years messing with two strokes got me that way. When those go lean you rebuild.

 

[LightningTeg]

You’re just fine. In my opinion anyway. It might be a bit rich, but as long as it revs good and doesn’t sputter or ever lose power, it’s not a problem. You might foul a plug here and there, but rich is better than lean. But I know people will disagree with me on not worrying about it.

It so low on compression probably not a big deal if you go either way a little bit. Just make sure to run premium

 

[J.S.@SMS]

If it's available, run recreational fuel (non-ethanol). It'll save you some money from not having to rebuild your carbs.

 

[65ShelbyClone]

First of all, it looks like you simply pulled the plug after running the engine around for some time. We can't tell anything based on that; you need to start with a new plug and do a proper "plug chop" test.

Second, oxygenated/reformulated/etc pump gas is going to make plug reading difficult at best. All the plug reading charts you'll find likely date back to the unoxygenated gas days, if not leaded gas era(roughly pre-1974) and are not very representative of what you'll see nowadays.

Based on your photo, yes it's rich somewhere. Could be the idle, could be the pilot, could be the main, or could be a combination.

And don't bother using premium gas with stock compression unless the plug shows that it's needed.

 

[Flyinhillbilly]

First of all, it looks like you simply pulled the plug after running the engine around for some time. We can't tell anything based on that; you need to start with a new plug and do a proper "plug chop" test.

Second, oxygenated/reformulated/etc pump gas is going to make plug reading difficult at best. All the plug reading charts you'll find likely date back to the unoxygenated gas days, if not leaded gas era(roughly pre-1974) and are not very representative of what you'll see nowadays.

Based on your photo, yes it's rich somewhere. Could be the idle, could be the pilot, could be the main, or could be a combination.

And don't bother using premium gas with stock compression unless the plug shows that it's needed.

My name is Flyinhillbilly and I support this message.

 

[950speed]

Sorry for getting back too late, I went and bought two new plugs, and what I have done so far is put the stock jet in. Pictures are attached

Things I noticed:
1. No more crackling, the richer jet would cause a pop sound upon deceleration
2. Smoother acceleration
3. Wider power band( at least it seems like it)

Things I’m still curious about:
1. Why does the lean jet seem to work better

Thanks guys for everything so far!

The pictures are after running at higher rpm (~3500) for 15 minutes only. Although with he stick jet, high flow air filter/exhaust the engine does seem to have a bit more power, then again it’s my first time doing this.

Previously with the .038 jet that came with the kit, I would only experience more power at high rpm, and even still then the plug was really dark.


Side question: would drilling out the idle jet have an affect on lower rpm acceleration and power?

 

[itsid]

that's what I'd call a near perfect plug!

I wouldn't even think about touching a setting!...
different air humidity and temperature is what the miniscule offset is coming from IMHO
(a perfectly dialed in air/fuel ratio early in the morning in your cool garage looks like that
in the heat of a summer afternoon)

still a bit glossy on the electrode (bit rich)
but a nice spark and thorough combustion (perfect coloured insulator)



[EDIT]
drilling out the idle is not a good idea, you still want the needle to seat perfectly, so reaming
would be the way to enlarge it... (I wouldn't even try)
it's essentially the same as opening up the idle jet with your setscrew. (what you could try instead)

Yes it's add fuel to the low speed "circuit" but
since you cannot do that without affecting - you guessed it - idle
[at which it's the single source for fuel];
you'd need to close that gap again in order to not foul your plug before taking off...
(so no more allowing the engine to heat up before a 'race')


'sid

 

[950speed]

that's what I'd call a near perfect plug!

I wouldn't even think about touching a setting!...
different air humidity and temperature is what the miniscule offset is coming from IMHO
(a perfectly dialed in air/fuel ratio early in the morning in your cool garage looks like that
in the heat of a summer afternoon)

still a bit glossy on the electrode (bit rich)
but a nice spark and thorough combustion (perfect coloured insulator)



[EDIT]
drilling out the idle is not a good idea, you still want the needle to seat perfectly, so reaming
would be the way to enlarge it... (I wouldn't even try)
it's essentially the same as opening up the idle jet with your setscrew. (what you could try instead)

Yes it's add fuel to the low speed "circuit" but
since you cannot do that without affecting - you guessed it - idle
[at which it's the single source for fuel];
you'd need to close that gap again in order to not foul your plug before taking off...
(so no more allowing the engine to heat up before a 'race')


'sid

Okay great! I was just confused, because it’s the stock jet being used, while more air is coming into the engine because of the air filter. And more power feels like it’s being made.

Any idea as to why this jet still works good, I’m still curious?

 

[JTSpeedDemon]

Like 'sid said, there's a lot of variables that will affect it, namely air density and temperature, and the mixture screw setting. There's probably just not as much air as you think flowing through, so it doesn't need that much fuel through the main jet.
If it ain't broke(anymore), DON'T FIX IT!

 

[950speed]

Like 'sid said, there's a lot of variables that will affect it, namely air density and temperature, and the mixture screw setting. There's probably just not as much air as you think flowing through, so it doesn't need that much fuel through the main jet.
If it ain't broke(anymore), DON'T FIX IT!

So it’s all possible because of air density, and I still get more power? I have stage one kit, not trying to argue but just confused



Is it heard of to make more power with stage one without rejecting? Again I don’t know if this makes a difference, but with the rich jet it made more power up at higher rpm it felt like.

 

[mckutzy]

First... these clone carbs for the most part aren't adjustable asfar as the mixture screw is concerned... that is what a plug test and redrilling the jet does... it sets it to the right "setting" for proper combustion...
The adjustable screw is typically not present on most carbs here in N. America due to environmental constraints...and that is just the idle jet mixer....

 

[950speed]

??^