stock NT carb problems

[FreeWheeler]

My 2 stroke from DAX is running like crap, no power, runs extremely rich. I've had the carb apart about 4 times now and cant figure out what's wrong. I did find the pin in the float tang fulcrum was out on one side, so the tang only supported on one side. I dont know if this happened when I took it off, but I'll be extra careful when I put it back not to tilt it to one side. Another thing I found is that there is no little tit for the barrel slot to ride in.

1) Is this how they come now or did my engine eat that little tit and wont ever run right again?

It backfired and whoofed today and started to run but it went back to overly rich. I lost my idle screw and have it plugged with a dowel but it doesnt protrude into the barrel, so I get no alignment from an idle screw.

2) If the barrel slide isnt guided and rotates and wanders around the spring and pin, can it rotate into a position that causes flooding?

 

[bairdco]

without the guide pin, the slide could rotate. when you twist the throttle, it could cause the slide to spiral as it follows the twist of the cable.

even worse, the guide pin may have been sucked into your motor, which could cause damage to the piston and the cylinder walls. or best case, it got shot out of your exhaust.

not having an idle screw is a slightly lesser problem, but without proper adjustment, you'll never get the carb tuned right.

i think it's time to break down and buy another one.

 

[FreeWheeler]

Maybe the first engine ate it, ha ha.

I havent totally given up on this carb yet. It ran pretty good today with no aircleaner and c-clip all the way up, so I took carb off again. I turned the carb upside down and blew through the fuel line and the float needle seals it shut. I adjusted the tangs on the float so that the float sits level and even with the jet.

It seemed like the primer pin could have been blocking the float from closing the valve if things got bouncy in there?

 

[FreeWheeler]

without the guide pin, the slide could rotate. when you twist the throttle, it could cause the slide to spiral as it follows the twist of the cable.

even worse, the guide pin may have been sucked into your motor, which could cause damage to the piston and the cylinder walls. or best case, it got shot out of your exhaust.

not having an idle screw is a slightly lesser problem, but without proper adjustment, you'll never get the carb tuned right.

i think it's time to break down and buy another one.

I'm not throwing money at it unless it's worth it. Here's what I did tonight. Toook the carb apart again! I heated the jet up with a lighter for about 2 minutes with a really small drill bit as a heat sink. That bit was glowing red and then I touched the jet hole with some rosin core solder wire and it crackled as it melted the hole shut. I waited for it to cool and then I undrilled the bit.

I figure it almost runs right, idles nice, and rejet again is the next step since it is soooo rich. The slide is stable even without the guide pin, just watching it idle without the air cleaner and blipping the throttle. It is so rich, in fact, that it only runs without the air cleaner and I really dont want to do that.

 

[FreeWheeler]

Well, I threw some money at it. New and bigger air cleaner from pirate. The rejet worked as I was able to run it with the stock air cleaner, but it still will go along smooth and just cut out. When it does this, I can wait about 30 seconds and it starts. No pattern to when it will act up.

 

[Dave31]

Well, I threw some money at it. New and bigger air cleaner from pirate. The rejet worked as I was able to run it with the stock air cleaner, but it still will go along smooth and just cut out. When it does this, I can wait about 30 seconds and it starts. No pattern to when it will act up.

Are you saying it cuts out completely? Almost sounds like it bogging or crapping out which is very common with these motors. Have you checked your motor mounts? Sometimes if your mounts are not tight the motor vibrates to where it creates a fuel delivery problem.

 

[FreeWheeler]

Hmmmm, vibration is different lately, higher frequency. It gets up to speed and I can feel little surges and then it might smooth out for awhile or I might get the big cut out.

Big cut out is dead, engine stops running like I used kill switch(not hooked up since problems).

 

[Dave31]

Hmmmm, vibration is different lately, higher frequency. It gets up to speed and I can feel little surges and then it might smooth out for awhile or I might get the big cut out.

Big cut out is dead, engine stops running like I used kill switch(not hooked up since problems).

Man, it sounds like something so simple but so hard to determine without being able to mess with it.

 

[FreeWheeler]

I did three things to it tonight, moved the float higher and resoldered the magneto connectors including the single strand ground. The wires are shiny solder now and resistance checks.

I also checked the motor mounts and they were tight, except the oversize adapter U-bolt is stripped on one side and more threads showing on one side. What I did was shift the U-bolt so the threads show more even and then I was able to go beyond the stripped spot till tight. I might end up replacing that.

I'll test it again today, thanks Dave31.

 

[bairdco]

check where your ground wire connects to the frame, or whatever you grounded it to. that could've come loose, got corroded, or something.

also, trace your plug wire from CDI to plug. it might've unscrewed from the cdi, or rattles on the plug, causing an intermittent inturruption.

 

[FreeWheeler]

It ran like a champ today, bairdco. Maybe my wiring Was part of the problem and just resoldering ground and blue wire on the mag didnt hurt, seems to fire alot stronger. Adjusting the float a hair higher took care of the little surges, I believe. When the new air cleaner gets here, I'll know if that allows it to breathe as well as no filter. The blowback is clogging up the stock one.

Is it too late to run Opti?

 

[bairdco]

glad to hear it.

as far as running opti2, it's something you'll have to find out for yourself. me and 2door were the only ones who seemed to have problems switching and old motor to it.

ya never know what results you're gonna get.

if you do decide to try it, make sure you work out all the other problems first. that way if it runs bad (or better) you'll know it's the oil, and not the carb, the wiring, the...etc...

 

[FreeWheeler]

It's still running good. I ran it with two different filters and both breathe great. One cost nothing and the other has bling.

 

[FreeWheeler]

I can declare success for now. I was getting a ton of blowback mess and now I'm not. The latest change was I went one drill bit smaller on the jet. When I ran without a filter, it ran so good but I knew it was very risky. When I tried more breathable filter arrangements, it ran good but I could tell a slight difference because it didnt 2 stroke quite as easily. I figured the blowback with no filter is leaner since it all gets ejected and with a filter some blowback gets sucked back up, richer(my guess). When I went down one more on the jet, that was the final touch. Now It busts into a 2 stroke and stays there and no visible oily drip from the filter.

Now is probably the time to try opti2 if I'm going to.

 

[FreeWheeler]

Here's my plug after rejetting and running a day or so. Looks fine line too close to lean to me maybe?

 

[FreeWheeler]

I switched to Yamalube 32:1. I gps'd my test route and no difference in top speed(25MPH). The dealer said he had too many engine seizures with amsoil and never heard of opti. :0

 

[Apollo 66]

Hi guys, hoping you can assist me. I am running the NT carb on my 66cc and since moving to a colder climate I seem to have lost power. Should I be adjusting the clip. The plug is still tan in colour?

 

[crassius]

these engines take quite a while to warm up to a stable operating temp, you may have gone from a 4-5mile warm up to a 6-8mile warm up

not sure why 2-strokes take so long, but suspect that having those two big crank wheels as part of the intake path might be part of the problem

 

[2door]

Hi guys, hoping you can assist me. I am running the NT carb on my 66cc and since moving to a colder climate I seem to have lost power. Should I be adjusting the clip. The plug is still tan in colour?

A colder climate? How about elevation? Are you higher above sea level now? Altitude plays into how an internal combustion engine will run and how much power it will produce. Higher = less power at a given fuel to air mix.


The clip position only effects the mix from off idle to about 3/4 throttle. After 3/4 the needle is out of the equation and the main jet size determines fuel flow.
Tom

 

[Apollo 66]

thank you. i will play around with jet sizes.

elevation is similar.

Regards