Oily Spark plug

[captaingeech]

I have a 2 stroke 49cc engine. I'm very new to this, and I didn't assemble mine but bought it second hand and am trying to learn from here.

The engine was very new when I bought it, maybe had run 1 gal. I ran it for about a week (another gal.) on the recommended 25:1 oil to gas mix, then it started to sputter and die. The spark plug was super oily and gross and oil was dripping from the exhaust. Also, there was some oil on the air filter. I cleaned the plug and cut it back to 40:1. It ran fine.
A week later it started to jerk and died again. The plug was very oily again, but no drippage from the exhaust, so I think it was a little better. I cut it back to 50:1 and put in a brand new plug (NGK B7Hs) gapped at .025. I changed the air filter. I used super unleaded gas and Motul 800 2T synthetic oil and ran it for another week and the plug is still looking really oily. I cleaned it and it has been running fine. It hasn't died yet, but it seemed to be getting a little jerky again today though.
I have no idea how to adjust the e clip in the carb, which I've heard other people talking about, if that would make a difference. I don't know if that is simple to do, or if that would be a possible fix. Other than that I have no idea how to keep the plug from getting oily. I would greatly appreciate any help that can be offered.

 

[DonnnN]

Ok check this thread out.. It should give you all the info you need about adjusting the clip


http://motorbicycling.com/f13/carb-needle-clip-settings-7480.html

 

[BarelyAWake]

erm... no - that's part of the float mechanism, there's usually little need to mess w/it and it doesn't effect yer mix at all. Worst case is if it's bent down too much you'll just "run out of fuel" at wide open throttle, bent up too much and the float can hit the primer pin and not seal completely - making a puddle under yer bike as fuel pours outa yer carb lol.

The E-clip and it's setting is usually a fuel/air adjustment reference and it's to be found on the needle inside the carb's slide;

Moving the clip "up" (towards the flat end) leans the mix (more air/less fuel), moving the clip down (towards the pointy end) enriches the mix (less air/more fuel). Sounds like yer runnin' rich, no surprise lol - try the clip on the second notch down from the top and work from there.

Hope that helps

edit: BTW - when reassembling the carb, there's a lil pin on the inside of the carb that needs to line up with the slot on the slide, else it wont go back together/you'll break it/it'll stick;

 

[Bikeguy Joe]

Excellent advice and great photos Mr. Awake.

 

[Bikeguy Joe]

The "E" clip is also known as the "C" clip. The float adjustment arms are called just that, and have not too much to do with the carb other than keeping the float in the proper range of operation.

Anyhow, I think you are running a little rich fuel to air wise, not gasoline to oil wise.
Move the clip UP a notch as stated above, not DOWN as stated above the above...

 

[xlite]

erm... no - that's part of the float mechanism, there's usually little need to mess w/it and it doesn't effect yer mix at all.

Not quite true. Raising the float level will richen mixture and versa visa. Also note that raising/lowering needle only effects low end. For WOT the float level and jet size matter. Since changing jet is a pain it is much easier to bend the float prongs. Good idea to measure where they were when you start so you can get back to original setting if that's not the problem.

It is true that if level is too high carb will leak and if too low will starve. Then it's time to get out the tiny drill or soldering iron and play with the jet.

 

[captaingeech]

Much appreciated everyone! I'll be trying that out soon, and will let you know how it goes. This site rocks!

P.S. What's WOT?

 

[george_n_texas]

WOT = wide open throttle I assume I wondered for quite a while myself. I don't doubt much advise here but I gotta wonder how the level of fuel in the bowl is gonna make a difference in lean...I saw a thread on adjusting the idle screw with the same result...idle speed and lean are like the difference in child support and alimony both are wrong in excess.

 

[BarelyAWake]

Yar, WOT = Wide Open Throttle lol, took me some time to get used to that as I've always known it as Wall Of Text...

Not that I tend to ramble on and on or anythin'...

 

[xlite]

WOT = wide open throttle I assume I wondered for quite a while myself. I don't doubt much advise here but I gotta wonder how the level of fuel in the bowl is gonna make a difference in lean...I saw a thread on adjusting the idle screw with the same result...idle speed and lean are like the difference in child support and alimony both are wrong in excess.

You would be wise to doubt much of the advice here as about 2/3 of what you read on the net is bogus. (NET=Not Everythings True). In fact you should independently verify anything I say.

I find it amusing that many think the needle clip has any effect on open throttle ratio at all but are clueless about the influence of fuel level. It's also entertaining to see how many think the idle SPEED screw has any effect on ratio. These are generally the same guys who say adding more oil to the gas makes it "richer" or runs cooler. In fact the opposite is true.

Unfortunately most tend to believe advice from those they adore rather than those who are right. Often they are victims of individuals who profit from gullibility. Often just "the Blind leading the Blind". IMO people deserve the consequences of their choice though.

As far as the float, the closer fuel level is to the opening in the carb the more pressure is exerted forcing more fuel through the jet in a given period of time (richer). A simple 5 minute experiment is very convincing. I personally didn't appreciate how much effect the level had until trying it myself.

 

[xlite]

Yar, WOT = Wide Open Throttle lol, took me some time to get used to that as I've always known it as Wall Of Text...

Not that I tend to ramble on and on or anythin'...

That WOT from 2door you posted was worth it's weight in gold.

 

[BarelyAWake]

hmm... I've done that "simple 5 minute" experiment myself and I must say the results were... well less than "convincing" lol

Having said that, I'd like to point out that these kits are all over the place insofar as "tolerances" go, so what doesn't work for one may be just the ticket for another *shrug*

Keeping your above NET and other advice in mind, I try to limit my advice to the very basics of function, using the lean/rich as an example - the "proper" way to adjust it on these carbs it pretty much limited to jetting and needle clip settings. While you may indeed get variance in "mix" due to float level adjustment, I suspect that's a result of your float being at the incorrect height to begin with. Once its "fixed" yer done with it.

Which is ofc a slightly different problem, a starvation issue - not really a fuel/air mix adjustment, although the end result is somewhat similar. Whereas with the actual fuel/air adjustments you may find it needs continuing/additional tinkering due to temp/air density and even what oil/fuel mix you like. When making a "remote" diagnostic of someone's problems, it's prolly best to start with the standard technique - once the fuel/air mix is set and there's continuing problems like cutting out at speed - then I wonder about things like float level.

I usually skip over such fine distinctions initially as not to mislead or confuse. We all have our "pet" favorite tweaks, not all are as relevant as actual engine basics and the "standard" repair techniques. KISS really is best in most cases

That WOT from 2door you posted was worth it's weight in gold.

Yus - yus it was Tom is ossum lol

 

[xlite]

hmm... I've done that "simple 5 minute" experiment myself and I must say the results were... well less than "convincing" lol

Then you didn't do it right. Either you failed to test at WOT, the jet was way off, or you didn't go far enough. If you bend the prongs down to just above starving the plug will be grey and motor will not stop with choke. Up til it almost leaks the plug will be black and it will 4-stroke at WOT. It is equivalent to several jet sizes.

 

[xlite]

using the lean/rich as an example - the "proper" way to adjust it on these carbs it pretty much limited to jetting and needle clip settings.

The needle clip position has little effect at WOT where most people are having issues. Soldering/drilling or ordering new jets is a non-triival task compared to bending prongs.

We all have our "pet" favorite tweaks, not all are as relevant as actual engine basics and the "standard" repair techniques. KISS really is best in most cases.

You and I have different definitions of KISS. I've solved several ratio problems (plug color, 4-stroking, etc.) in less than a minute by popping bowl off and bending prongs. How long does it take to redrill or order new jets?

The only real risk is if ratio was not the trouble to begin with and noobs fail to get those prongs back where they were.

 

[BarelyAWake]

...and my carb's float is set dictated by the angle at which the carb is mounted - in my case so extreme as to limit any adjustable range there may have been were it mounted level, unfortunately this also means I can't experiment with your suggestion.

I have noticed how few level types we have around these parts

I'm not 100% sure how much an effect the "regulation" of fuel into the bowl would actually have beyond restricting it to the point of starvation. The only way I can see it having any effect is the extremes - literally pouring into the carb or simply not filling the bowl enough and cutting out.

The air comes from the throat after all, fuel should be atomizing as it comes out of the jet and not before - so how would float level effect mix if it's the needle that regulates this fuel stream? Where's the "air" coming from? I just don't see the float as being precise enough to regulate anything anyway as it bounces and sloshes around in there at speed beyond plugging and opening...

I could be wrong, gawd it's happened enough before lol But based on all my tinkering I've never considered the float as a viable means to adjust mix beyond "zomg its pouring out all o'er the floor" or high rpm starvation.

edit: I have never suggested drilling or rejetting, viable as they are - I have only referred people to setting the Eclip to adjust mix, dictated by plug coloration. Rejetting is way too regional (altitude) and thus precise to recommend specific sizes remotely, particularly when relying on a description alone heh

 

[silverbear]

Yar, WOT = Wide Open Throttle lol, took me some time to get used to that as I've always known it as Wall Of Text...

Not that I tend to ramble on and on or anythin'...

Well, I notice your posts have reached the thousand mark... ha! You contribute much here. Nice picture tutorial.
SB

 

[BarelyAWake]

Hey thanks silver! It's good to be here lol

(1001 heh)

 

[george_n_texas]

I am sure one could change the fuel richness by float bowl...the other day someone was said he was doing the same thing by not opening the petcock all the way hence limiting the flow. That's kinda like not giving straw to people trying to make bricks...whadayknow Al they aren't making as many bricks for some reason today LOL

I noticed one of the senior people told the guy that's dangerous as it could lean the engine too much causing damage. Do you know how it feels to be thick as a brick? (Jethro Tull)

 

[BarelyAWake]

um... I still think that would lead to erratic fuel starvation - which isn't quite the same thing as adjusting your mix...

 

[xlite]

...and my carb's float is set dictated by the angle at which the carb is mounted - in my case so extreme as to limit any adjustable range there may have been were it mounted level, unfortunately this also means I can't experiment with your suggestion.

That certainly explains why you've had bad luck trying this. I keep my carb perfectly level as I never use the gas petcock.

I'm not 100% sure how much an effect the "regulation" of fuel into the bowl would actually have beyond restricting it to the point of starvation.

"Regulation of fuel into the bowl" is not a practical or safe method to control ratio. Unrelated to setting fuel level with the float.

edit: I have never suggested drilling or rejetting

In post #12 you described "jetting" as a "proper" way to adjust mixture. I think we agree it is not the easiest way.