Bought new Oct 2004, ran great for about 30 days. When it got cold it would not run. It has the electric choke on it. I replaced the carb, the choke unit and float. still does not run. If I turn the mix screw out 9 full turns it will start and once it warms up set the mix screw at 2 turns out, you can now ride it. But don't shut it off and let it cool down. I really need a manual choke carb. Help JBR

 

If you have to turn the mixture screw out 9 turns, I'll bet something in the carb is plugged/dirty.

 

I tore the 1st carb down and cleaned out very good. It was not dirty at all, because it only had a few hours on it from new. The 2nd carb acts just like the 1st one. There are two wires coming out of the electric choke mix unit (whick also was changed) these wires lead to the magneto unit. With the quad running I can disconnect the wires, with no change in the quad running. I also get no reading of any electric power on these wires. It is my opinion that what ever sends the electric message to the choke unit is not working. There must be a cross over to a manual choke carb for this machine. Thank you for your come back JBR

 

This carb problem is out of the ordinary. My friend has a kazuma 150R and he didnt have any problems.

 

I've noticed a lot of these Chinese quads have carb issues. My only issue on my Yamoto 150 is that I have to lightly hold the throttle with my thumb during warm up to since it doesn't seem to have any kind of choke. No biggie because once it warms up it runs like a champ. Once warn, one push of the electric start button and it fires right up every time. CVT tranny, electric start, lever brakes....this thing is easy to operate for anybody. My kid got this down after about 30 minutes.

 

I have two KMZ 150's and they start hard during cold weather. This is what I found out - the carburetor has what used to be called a by-starter in lieu of a butterfly choke valve. The bystarter has a plunger valve that is retracted during a cold start. The electric actuator is really a heating element that over a period of time extends the plunger. When the plunger is fully retracted (during cold start up) the engine should see a rich mixture than usual to help with cold starting and provides for a higher idle. As the engine warms up and the actuator head heats up, the plunger valve extends leaning out the fuel mixture back to normal thus decreasing the idle speed back to normal. The only way for this cycle to work is leaving the throttle position at dead idle during starting. From what I read, the bystarter is supposed to introduce air into the jetting of the carb in a certain way to cause more fuel to flow thru the low speed jet. I always thought more air meant a leaner mixture but the article I read was kind of vague. Do a search for by-starter on the net and after some searching it will bring up an old honda motor article. I have not been able to get these things to start in the cold without cranking on the starter and having them stall out several times. After the atv warms up they start fine. I have cleaned the carb, set the idle and low speed mixture at various settings. I had one bad by-starter actuator and Raceway is sending a whole new carb, but I don't think it will solve the problem. The actuator would not extend. I think these engines are cold blooded. I have had two stroke dirt bikes with by-starters and they worked just fine but for some reason these don't or I just havent had any luck with them. Anyhow I do have a solution. I added a primer button to one of the atv's and I am going to do the same to the other if the new carb does not work. They sell these as kits at any atv store. Two pumps of the primer button and a little throttle and viola - ignition without hardly any cranking on the starter. Very rare will it stall and need a repeat. The avt 'still needs warm up time but at least I am not cranking on the starter. What I have noticed is that with the primer you have to crack the throttle a little when starting. If you go this route be careful where you route the primer lines. Good luck

 

We have 2 Kazuma RFX-150's that we bought from RacewayATV in Dec 2004. One of them starts on the first crank, every time, no matter how cold the weather.

The other one...well...not so much. Crank and crank, finally eventually will start and die a few times, then blurbles along, and finally smooths out.

I bet it is the auto bystarter - good call PropMaint!

I'm going to try this next:
http://www.scootertherapy.com/nqchokepage.html

Let us know if the new carb fixes your problem.

 

Hmm....Scooter Therapy didn't work.

Did what they said with the auto bystarter, but it didn't make any difference at all - still wouldn't start until the 15th try, and then died, started/died, for about 5 more tries. Finally got it started, rough idle, but eventually smoothed out.

Any other ideas why it's so hard to start?

 

Thanks for all the help. The manual calls it an electric choke, bystarter sounds good to me. Having this apart a few times and installing a new bystarter and a used (different carb). The unit in question is more than just a electric choke. It has a barrel slide that covers and uncovers two ports in the carb side, also a needle that goes into a seat in the carb. If you remove the unit and cover the hole with your thumb you can start and opperate the quad fine but with some difficulty. The two wires from the bystarter appear to go to the magneto. Mine have no voltage on the wires even with the quad running. With the by starter installed and turning the air screw out 9 full turns allows the quad to start allowing it to warm up now turn the screw back in to about 2 turns out the quad can be riden. I,m still hoping for a manual choke carb. Thanks again

 

I sure wish I could help you guys. I went to fire up my wifes quad yesterday, it would start run for a couple seconds, die. Took carb off, completely apart, sprayed carb cleaner through it. Then blew thru it with compressed air, put it back together and it fired right up, high idle for about 45 secs, ran like a champ. Do you guys take the carb completely apart, choke mechanism and that plate with the vac line going in it? Just curious, because my wifes yamoto e-choke looks just like the scooter therapy link. I have had to clean carb about every 10 weeks, usually after sitting a while.