Kandi 150cc stator / rectifier test help

[nailzscott]

I bought a used GB150 go kart with issues. With new carb, it runs but has problems under load - bogging down above probably 15mph. I've done gas and air tests and all that seems fine. I recently did stator and rectifier tests but am having trouble interpreting the results. I cannot find an exact electrical diagram to my cart but have used the closest that I could find.

Stator test
Disconnected wiring, run up RPMs and tested Pickup wire at .15v. I've read target should be .3 - .5
testing Excitor wire. run up RPMs, and got 44v. Expected target base upon what I've read is 50v.

Adjusted reluctor to pickup gap closer - but no significant change.

Just guessing, but does that mean a bad stator?

Plugged all back in, tested wiring at rectifier running at higher RPMs.
Red wire tested at 13.5v DC. White wire (runs stator to choke & rectifier on mine) was 10v AC (not good I'm guessing and also why choke may not be working). Yellow wire (runs stator to rectifier) was 35 volts. Do these readings make since - I thought both white and yellow were supposed to put out just better than battery voltage.

Hoping someone can help

[SYCARMS]

First you will need to determine weather you have an AC or DC volt setup. If a DC volt system you can go to Americanlandmaster.com and download the service manual for a 6150 or 7150 150cc engine . You do not check readings while running. You check the pickup, stater and coil using an ohm meter, there is no way to check the CDI. If you have a good coil and blue spark the pickup is good. If a weak yellow or orange spark suspect either the coil or spark plug. If spark is good you will need to know what compression is by doing a compression test and also check the valve adjustment. If all the above is good you will look for a vacuum leak, bad fuel or carburetor.

[nailzscott]

sycarms

Thanks for the link to some manuals. They don't look exactly like my kart, but the wiring for the 7150 matches mine pretty close - except for wire colors. I'll check the pickup and stator resistance next if I can find those measurements in the manual.

As far as AC vs DC, my understanding was that the stator generates AC volts (which I was able to measure) and some of those stator wires go to the regulator - which then converts to DC volts to charge the battery.

The spark is blue and the compression is around 120 (may be a little more but I was having trouble holding the pressure gauge while turning the starter. New carb and vacuum lines appear to be working fine.

So that might take me to checking the valve clearance

[nailzscott]

Sorry, hit the post button too quick.

Looks like I have some reading and testing to do.

Thanks for the help.

[SYCARMS]

How many wires are going to the 2 pin side of CDI?

[nailzscott]

2 wires from the 2 pin side of the cdi - one is the pickup wire from from the stator and the other goes to the coil.

[nailzscott]

I did the ohms testing and something is very odd. The pickup wire shows 135 ohms. The excitor wire shows 390 ohms - but only for a split second, then drops to zero. I did my original testing based up this video, which basically says the ohms test may not be the best way to test chinese scooters due to the variation in what the various manuals say the ohms should be.

http://www.youtube.com/watch?v=q9-mr7BXIho

Testing volts based upon the video, I get 44vac on the excitor - which had the unusual ohms, then dropped to zero.

This cart runs exceptionally well up to about 1/2 throttle - that's when in bogs down. Can this be caused by a valve adjustments; or if that was the problem, would it run poorly throughout the throttle range.

Thanks

[SYCARMS]

As I stated earlier if you are getting a good blue spark your stater and trigger are good. If positive that you have no vacuum leak, carb is good and properly jetted, fuel is good then I would suspect the CDI. Does your Kandi have an external or internal reverse?

[nailzscott]

It has a reverse lever on the kart's dash.

So running great at half throttle and poor above that can be the cdi?

[SYCARMS]

If everything checks out good than CDI will be suspected. Not sure what exactly the symptoms are but if the engine is not misfiring it could be that the CVT is not properly working. Bad or stuck rollers or clutck will keep it from shifting. However I cannot state how many times customers have told me they had good fuel and the fuel was the problem. 10% ethanol fuel will go bad after sitting for 2 weeks. Best to use non ethanol fuel. Also you mentioned that you had a new carb. First they are jetted for scooters so jetting in buggies will not be sufficient. Many of the $30.00 carbs from E-Bay are crap. You could still have a bad carb or possibly not getting power to the enrichment valve causing a too rich mixture when engine is warmed up.

[nailzscott]

I have a new carb since the old one kept sticking and dumping fuel. New carb (local dealer) seems to work fine, new gas, new vacuum hoses, no intake leaks, new spark plug, good blue spark.

About the CVT, will it do this: kart is on jack stands in seems to run up to full throttle. Set it down and take off and it runs fine up to about half speed, then stepping on the throttle seems to bog it down.

[SYCARMS]

Being the buggy is used and new to you, you need to check everything including the cvt, compression, valve adjustment. Things you have to have " good compression, good blue spark a good proper mix of air and fuel " for the engine to run and perform. It is a process of elimination. You know you have a good spark. Do you know your compression, jetting, proper valve adjustment, condition of CVT system? Just like going to a doctor there will be several specs he'll need to know about you weight, age , height, BP than your reason for visit with several questions pertaining to problem. Just like a doctor the more accurate info you give (not assumptions or guesses) the easier to diagnose the problem. That manual will guide you through the checks for the info you need to diagnose the problem. Once everything is known about the overall condition and it checks good than you would suspect the CDI. Normally the CDI either works or don't, but in very few instances I have had the limiter go bad as not to allow the normal RPM output needed to get up to speed, and at times just the wrong or new defective CDI. The reason for the CDI be suspected last is that it is the only component that cannot be checked. A video would be helpful.

[nailzscott]

adjustments for highest idle, put the air box back on but without the filter and cover. He ran just like before, bogging down at higher rpm. An empty air filter box with nothing in it was enough restriction to make it run bad. I've worked on cars and motorcycles for 45 years and I would have never believed it if I had not seen it.

What can cause such an issue?

[nailzscott]

Sorry, my post details were pasted in and got the front cut off. Here's the corrected detail.

During testing I discovered an oddity. Pulled air filters out of air box and it ran better, made carb adjustment to highest idle, put the air box back on but without the filter and cover. It ran just like before, bogging down at higher rpm. An empty air filter box with nothing in it was enough restriction to make it run bad. I've worked on cars and motorcycles for 45 years and I would have never believed it if I had not seen it.

What can cause such an issue?

Air box off and it runs perfectly fine and obviously I cannot run it without a filter.

[SYCARMS]

Did you check the air box for a blockage of some type? Mice will build nests in the hose. I personally get rid of the air box, make you a red neck cold air then put a UNI on it. Just keep in mind the UNI's are good but need oiling therefore more frequent cleaning and oiling of the filter is required. K&N are also oiled but with a prefilter installed over it cleaning and oil is required less often. The best are the R2C poly cotton gause filters, you don't oil just blow with air pressure to clean.

[nailzscott]

Checked air box - its clear. I'll check on the filters you mention. Still, won't any air filter put as much restriction as an empty open air box.

[SYCARMS]

If plugged it will, but the air box as a whole is very restricted in new order. That is why you need to know what jet is in the carb.

[nailzscott]

I can check with the dealer I bought the carb from; but does this issue appear that I would need a bigger jet or smaller.

[SYCARMS]

I don't know I don't see your spark plug. You need to see what jet is in there. Those manuals will tell how to do anything on that engine mechanical.

[neo71665]

My experience with engines if it runs like crap with the filter and fine without it's normally too big of a jet. With the filter it's getting too much fuel and not enough air.

Being an used buggy of unknown condition and maintenance it's really anybody's guess. To find out for sure you are gonna have to read the plug.

[nailzscott]

Thanks guys. Now that I can run it for a few minutes, I'll look at the plug. I'm going to talk to the dealer I bought the carb from before I tear it down.

Thanks again.

[OLDKID]

On my first cup of coffee , so forgive me if I'm way off base . Lower than optimum compression equals lower than optimum vacuum . On a CV carb couldn't this affect the operation of the slide/spring ? I had one the slide would " chatter " at mid range and not reach high RPM . REDNECK REPAIR ... I cut a coil off the spring . Remedied .

[SYCARMS]

Yes if the compression is low enough, that is why I conveyed in a previous post that one must know the vital signs of the engine before spending the money on parts. Guessing is expensive knowledge is priceless.

[OLDKID]

10/4 , Roger .

[nailzscott]

I talked to the dealer and he did not have other carb jets, so I took the one off of the old carb - but there was no change. I then took the choke off of the old carb and put it on the new carb. That took care of most of the issue. I still have not got it out and run for a while but it looks good so far.

I noted that the new choke had twice the ohms resistance as the old one, so apparently it was not closing down for quite a while, so the old one seems to have done the trick.

Thanks all who have helped.

[Richelle]

Testing volts based upon the video, I get 44vac on the excitor - which had the unusual ohms, then dropped to zero.