Stage 1 predator kit not running right

[sl1mm80]

Hey I bought a used go kart the other day it has a brand new predator 212cc engine. The previous owner installed a stage 2 kit from omb warehouse. Everything except the larger jet and the 8 degree timing key. The motor was rough at idle but would Rev up fine. He said he talked to omb and they told him the rough idle was due to not having the key and larger jet in yet.

So I brought it home I put the jet in and the offset key, making sure the key was facing the correct way. Now it ides rough and won't take throttle. It puffs black smoke at idle. I tried putting the smaller jet back in but still the same thing. So I put the larger jet in again tried getting it warm and then it would take some throttle but if I gave it to much it would die.

I tried turning the mixture screw but I didn't notice any change....

So what am I missing?

 

[Thepartsguy]

Black smoke at idle is directly to rich blue smoke Is burning oil.

 

[Oilpan4]

Every engine I have put an advance key on definitely ran better so that's odd.
Is the carb flooding?
What was the original jet, what's it got now?
Are you sure there isn't a pressure port blocked?
I had a buckled bowl seal not that long ago after a jet change, it ran kind of like that, was able to fix it real quick.

 

[sl1mm80]

Not sure on jet sizes. I think only one had markings I will check tonight. I know most mixture screws are turn in for leaner and out for fatter is that still the same on these carbs?

 

[sl1mm80]

So the one I took out looks like a 0960 (hard to read) new one has no markings but is clearly bigger. I grabbed my Torch cleaner and was able to fit the one marked 57 in the 0960 jet and then able to fit the tip marked 61 in the un marked jet. The tube in the carb above the main jet looks like it says 236 not 100% sure. could be 136

The float is not sticking and I can see the needle bottom out when I raise the float. So I don't think it's flooding that way.

 

[BrownStainRacing]

So the one I took out looks like a 0960 (hard to read) new one has no markings but is clearly bigger. I grabbed my Torch cleaner and was able to fit the one marked 57 in the 0960 jet and then able to fit the tip marked 61 in the un marked jet. The tube in the carb above the main jet looks like it says 236 not 100% sure. could be 136

The float is not sticking and I can see the needle bottom out when I raise the float. So I don't think it's flooding that way.

You can't trust suppliers when it comes to jets and timing keys.

How do they know what main jet the engines wants??

How do they know where the keyway is cut at???

They don't have a clue.
Jus parts sellers waiting on the phone to ring so they can SELL you some more USELESS parts you don't need.

My advise is this,..... START OVER.

Figure out where you are at,......so you will KNOW which way you need to go.

Put the stock key back in, OR turn the advance key around.

The stock main jet should be .028". With a 1/32" drill bit, you can open it up to .031". This is a perfect STARTING POINT for a low compression stock engine.

Get a micro drill bit set and 3 or 4 stock main jets so you can easily open 1 up to the next size, til the porcelain on the sparkplug is a light to medium tan color. 2 or 3 plugs will be plenty.

The ignition timing needs to be verified using the stock key, a degree wheel and piston stop.

New in the box stock engines will come with 18*-27*, that I have checked so far. They ALL are different, and no 2 are the same.
So why do you need a +8* advance key when you don't know where it's at to begin with???

These stock low compression engines do really well with 28*-30* BTDC.

When you get too big of a main jet, you may have to start opening up the low speed jet also.
Stock low speed jets are .016"-.018", depends on the carb.
Japan made carbs are better then SP, and China made carbs, so the Japan made carbs can handle more jet on the low side, IF NEEDED.

They also dont interchange low speed jets, so you need to figure out what carb you have before ordering any low speed jets.

Here's a nice bit set for jets that make tuning alot easier. I've been using mine for years.
They also have jets and any other parts you may need.
My favorite vendor.
Straight up good people.

21 Pc Clone Jet Drill Bit Kit

www.doverpoweronlinestore.com

 

[sl1mm80]

Thanks for the info hopefully I can look into it this weekend.