Coil bind????

[Poboy kartman]

Yeah....it's running rich....now ....where and why????

This is just my two cents.....and I'm hoping someone will chime in with more experience.....but I think your idle jet is drilled too big.....

I would double check your float level as that is something that jumps out on me as well.....

Ditch your spark plug for now....and get a normal plug that runs hotter than stock.....(thats first, float check second and idle jet third)....does that carb have an adjustable main jet???? If so.....it's probably screwed out a turn too far......

I'm only going on general engine knowledge here.....maybe someone with more experience with that exact engine will help out.....

 

[Kart Simpson]

All sounds logical. Hotter plug is easy enough, checking float level Should be easy enough, and I have another clone (WEN) is the name brand. It has a ruixing (not sure of spelling) carb on it which looks identical to mine (all mine says on it is "SP") so I can pull that pilot jet and try that one. Main jet is not adjustable but I can try my stock one just to see if there is any difference if I need to. But like you said, hopefully someone else with the same engine can chime in here with some advise also.

 

[deano10972]

All sounds logical. Hotter plug is easy enough, checking float level Should be easy enough, and I have another clone (WEN) is the name brand. It has a ruixing (not sure of spelling) carb on it which looks identical to mine (all mine says on it is "SP") so I can pull that pilot jet and try that one. Main jet is not adjustable but I can try my stock one just to see if there is any difference if I need to. But like you said, hopefully someone else with the same engine can chime in here with some advise also.

Glad to see you at least got it fired up..

Those springs are different lengths so you won't get coil bind on the Hemi head engine, but it looks like you were fine before, all these China made engines are little different..
But I would stick to the new springs.

Sorry I didn't reply back I just seen your post.
I still have a stock cam.

My set up is .022 pilot jet and .039 main jet in a RuiXing carb and it runs perfect..I had issues with the stock carb also, mine would run but backfired a lot. The RuiXing carb has a mixing screw and a larger bore, it was only 20$ from ARC.

I would ditch that plug as mine didn't run right with it, I have the stock plug installed in it now.
Did you pull your plug out to get a reading after it ran for a minute?
You mentioned earlier that it would stall out if you gave it throttle, that tells me your main jet is not large enough.. Just my thought

I think your main problem is the plug.

I'm gonna read through your post again to see if I'm missing something

 

[Kart Simpson]

Well I can easily throw the stock plug back in and see how it goes from there. We are far apart on the main jet size tho. One thing at a time i guess. Thanks.

 

[Badot]

If you take your air filter off you can put your hand over the carb inlet to manually choke it. When doing that, if you can get it to rev up normally when you couldn't otherwise you'll know it's too lean. If it makes it worse, you're too rich.

Running too cold a plug will make the engine seem to run slightly lean, but it shouldn't be missing just from that unless you're way out.

Running for a minute then having to cool off before it starts again does sound like it's too rich though. Rarely a CDI box can stop working once it gets warmed up too, and will stop sparking until it cools down, or the fuel hose could be routed too close to the engine and give you vapor lock.

The backfiring likely isn't a huge concern right now, it likely just means that ignition missed on the power stroke and the wasted spark between exhaust and intake stoke managed to set off the remaining charge.

 

[Kart Simpson]

Thanks for the advise. Unfortunately I didnt get any garage time today. But at least I have a few ideas to try now. Hopefully be in the garage tomorrow. I will let you all know my outcome soon. Thanks again.

 

[Kart Simpson]

Well I was just in the garage for a bit. Changed spark plug. It fired right up as usual when its cold but stalled again and wont fire up again. So while I wait to be able to start it again I am gonna check the float, then see if that does anything. Then I will replace the pilot jet with a stock one that is on my other clone that has a ruixing carb on it. It looks identical to my carb. Hopefully get it to where it should be running some time today.

 

[Kart Simpson]

Well I think we did it!! Didn't do anything with the float yet but as I was going to swap pilot jets, I noticed that the rubber o-ring that should be on the bottom of it as you remove it wasn't there. So I looked down into the hole in the carb and it was sitting on the bottom. I am thinking that when I removed it originally to drill it out to .022 the o-ring was sitting on the bottom as well and when I reinstalled the pilot jet, it was on top of the o-ring. It runs now without stalling and when I shut it off myself, it fires right back up with one pull. So there is definite progress here. Seems it has to run a little high on rpm's in order to stay idle but its hard to tell without the centrifugal clutch on there. This carb doesn't have an idle screw, just a throttle screw. It appears to blow black smoke as well when it is running. Easier to see at low rpm's.

 

[Xtreme Yard Karts]

Well I think we did it!! Didn't do anything with the float yet but as I was going to swap pilot jets, I noticed that the rubber o-ring that should be on the bottom of it as you remove it wasn't there. So I looked down into the hole in the carb and it was sitting on the bottom. I am thinking that when I removed it originally to drill it out to .022 the o-ring was sitting on the bottom as well and when I reinstalled the pilot jet, it was on top of the o-ring. It runs now without stalling and when I shut it off myself, it fires right back up with one pull. So there is definite progress here. Seems it has to run a little high on rpm's in order to stay idle but its hard to tell without the centrifugal clutch on there. This carb doesn't have an idle screw, just a throttle screw. It appears to blow black smoke as well when it is running. Easier to see at low rpm's.

I don't know much about that specific carb, but if you're seeing black smoke at idle, it is still too rich. I also don't know the specs of the cam you are using, but it is not uncommon for big cams to have to idle higher than stock. I've had to cut a coil or two off the spring in a regular centrifugal clutch before to use them with race cams. I'm not sure how radical your cam is though, so I don't know if you'll have to do that or not. Race cams are designed to be used race clutches, and they engage at a higher RPM than stock centrifugal clutches...

 

[Kart Simpson]

I don't know much about that specific carb, but if you're seeing black smoke at idle, it is still too rich. I also don't know the specs of the cam you are using, but it is not uncommon for big cams to have to idle higher than stock. I've had to cut a coil or two off the spring in a regular centrifugal clutch before to use them with race cams. I'm not sure how radical your cam is though, so I don't know if you'll have to do that or not. Race cams are designed to be used race clutches, and they engage at a higher RPM than stock centrifugal clutches...

In this thread, at the bottom of page #2 I have a picture of the specs on a card that came with the mod 2 cam. What would you recommend for a centrifugal clutch? Just any "race clutch" or is there a specific one. I need 3/4" bore, 10 tooth, used with #40/41 chain and hopefully not to much money.

 

[Poboy kartman]

Just a couple of things....do you have a clutch? If so try it.....

"High" idle is pretty vauge over the net...could be well low enough to be below average clutch engagement rpm.....most CCs need quite high rpms to engage.....

I'm guessing just a little here....but I think a Hillard extreme duty clutch would be sufficient....but depends on whether you're a gambler or not..and how deep your pockets are.....

So a Hillard might run $50....a cheapy CC close to half that.....and a knock off TC about $125.......

Me....I would get the cheapy....and cross my fingers that it lasts at least 1/2 as long as the Hillard.....mainly because I never have any money....and I'm stupid that way.....the TC would be the best.....

You're running a couple of degrees advanced over recommended.....at some point....I would consider getting a 2° and 4° offset timing key....and try them to see if it helps.....regarding the timing should let it idle lower....just make sure you put them in backwards....lol...

While your idle jet wasn't drilled too big....the missing O-ring basically had the same effect....

Hang in there.... and welcome to the joys of engine modification tuning....

 

[Kart Simpson]

Just a couple of things....do you have a clutch? If so try it.....

"High" idle is pretty vauge over the net...could be well low enough to be below average clutch engagement rpm.....most CCs need quite high rpms to engage.....

I'm guessing just a little here....but I think a Hillard extreme duty clutch would be sufficient....but depends on whether you're a gambler or not..and how deep your pockets are.....

So a Hillard might run $50....a cheapy CC close to half that.....and a knock off TC about $125.......

Me....I would get the cheapy....and cross my fingers that it lasts at least 1/2 as long as the Hillard.....mainly because I never have any money....and I'm stupid that way.....the TC would be the best.....

You're running a couple of degrees advanced over recommended.....at some point....I would consider getting a 2° and 4° offset timing key....and try them to see if it helps.....regarding the timing should let it idle lower....just make sure you put them in backwards....lol...

While your idle jet wasn't drilled too big....the missing O-ring basically had the same effect....

Hang in there.... and welcome to the joys of engine modification tuning....

Yes I do have the cheapy $20 clutch I got off eBay. But I need to buy a new one anyway. The clutch for my daughters go kart is shot so I figured I would use the cheapy on that and get one a little better for the build. I also was looking at the Hillard earlier myself. $45 dollars is in the budget. But do I want to buy 1 Hillard or 2 cheapy's? I dunno, probabaly 1 Hillard. Not sure what the "TC" clutch is yet but I can figure it out but that seems to much money for my pocket. I am going to get the offset keys you mentioned. Hope there not to much money. I haven't looked them up yet. When I get them, I will need your help in guiding me on which way to put it in. I understand it needs to go in backwards to bring the timing the other way but I wont know what way that is by looking at it. More on that when the time comes. Off to search for timing keys.

http://www.ombwarehouse.com/Hilliard-s-Extreme-Duty-3-4-12-Tooth-35-R103891.html

 

[Kart Simpson]

You're running a couple of degrees advanced over recommended.....at some point....I would consider getting a 2° and 4° offset timing key....and try them to see if it helps.....regarding the timing should let it idle lower....just make sure you put them in backwards....lol...


Do I really need both offset keys? Or can I just get away with the 2* one. I am running a 32* btdc flywheel and a cam that recommends 30* btdc flywheel.

Also would there be a noticeable difference correcting that 2* difference?

 

[Poboy kartman]

Yeah....that's why I said you were running a couple of degrees advanced......I haven't priced them....but those things have got to be cheaper than the shipping.....and why not get both...?

You may want to use the 4° advanced with a stock flywheel in the future.....and while 30° is recommended....it doesn't mean you won't prefer the way it runs at 28°....and that way you can really tell the difference and how much effect changing the timing is making....

And don't forget about getting a hotter plug.....cheap enough thing to try as well.....

 

[Kart Simpson]

Yeah....that's why I said you were running a couple of degrees advanced......I haven't priced them....but those things have got to be cheaper than the shipping.....and why not get both...?

You may want to use the 4° advanced with a stock flywheel in the future.....and while 30° is recommended....it doesn't mean you won't prefer the way it runs at 28°....and that way you can really tell the difference and how much effect changing the timing is making....

And don't forget about getting a hotter plug.....cheap enough thing to try as well.....

Ok. As far as the plug, what plug should I get. I don't know what to ask for when I go to the store to get one.

 

[Poboy kartman]

......Me either.....bwah ....bwah....bwah.....station 51...go-karter in trouble.....Fireman Jim...please respond......

 

[Xtreme Yard Karts]

You're running a couple of degrees advanced over recommended.....at some point....I would consider getting a 2° and 4° offset timing key....and try them to see if it helps.....regarding the timing should let it idle lower....just make sure you put them in backwards....lol...


Do I really need both offset keys? Or can I just get away with the 2* one. I am running a 32* btdc flywheel and a cam that recommends 30* btdc flywheel.

Also would there be a noticeable difference correcting that 2* difference?

A lot of times a racing cam has recommended timing assuming you are going to be running methanol (or at least it used to be that way). If that is the case, you usually have to run a little timing with gas. It very well may run better with 28* than 30*, so I'd get both and experiment.

 

[Kart Simpson]

Ok gonna get both. The only place I could find them the cheapest seems to be from BMI Karts. They are $7.95 each (not exactly cheap) and then they want $15.41 for shipping!!!! Those things are so small they weigh next to nothing. I will probably wait until I have more money to purchase other stuff and combine the shipping. eBay is expensive too. If anyone knows another place, please let me know. When I hear Fireman Jims recommended plug, I will go to my local store and get one of those too.

 

[Poboy kartman]

They're more expensive than I expected....but try nrracing....they're 6.95 and the shipping to my place was $10.....

I would have expected 1/2 that....especially the shipping....try calling a small engine repair shop in your area....you never know.....

 

[Kart Simpson]

Well I fixed my black smoke issue. When I tore down engine to replace parts I reused the head gasket and it ended up leaking oil down the side of the block and some was getting into the cylinder as well. New copper head gasket fixed that problem. Still backfires a bit while holding the throttle a little. Ordered new 2 & 4 degree offset timing keys. Hopefully one of those will fix the backfiring.