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Swampy · 03-23-2017, 11:12 AM

I'm lazy so here is a cut and paste I found awhile ago on CV carb tuning. George (original poster) is working on 150 CC scooters which share the same power plant/carb as your Coolster.

How's everyone doing ? There are a few carb tuning threads out there , but I'd like to post a quick carb tuning tutorial. First here is a pic (Picture #1) of the most common unsealed150cc gy6 carb. This is your typical 24mm keihin carb. Is this a copy or is this the real deal ? To be honest we just dont know for sure. The copies have become so good that not only do they look good , but the work just as good also.

Here is a pic of the idle adjustment screw. (Picture #2)

And here is a pic of the air fuel adjustment screw. (Picture #3)

This tutorial is focused of tuning your carb with the air fuel and idle screw. Remember jetting may also need to be considered , along with vacuum leaks , if you cannot get the carb tuned correctly with these steps.

The first thing you want to do is start your scoot , after your scoot is warmed up and the autochoke closes of the extra fuel , you will next turn the idle screw clockwise so your rpms are a little higher then recomened, which would be anywhere from 1800-2000 rpms. Now what you want to do is turn the air fuel screw clockwise until the rpms begin to drop off. Next turn the air fuel screw counter clockwise until you get you highest rpms possible " be very careful , if your rpms begin to rise too high the clutch may start to engage , and the scoot could take off on you !! " to avoid this , you can back the idle screw off some by turning it counter clockwise dropping the rpms back down near 2000 , then you can continue turning the air fuel screw to obtain the highest rpm possible. Remember you only need to back the idle screw down IF you notice the rpms getting too high and the clutch wanting to engage. Finally , after obtaining the highest rpm with the air fuel screw , you will now want to use the idle screw to set the idle rpm back down to around 1700 .

After you have the carb tuned in properly, you may need to adjust the air fuel screw according to the weather. For instance , if the temp drops 30+ degrees , you may need to retune the carb due to the cooler dense air. These setups are very touchy when it comes to the drop in temps from season to season.
Hope this helps. Thanks , George

03-23-2017, 11:12 AM	#2
Swampy Join Date: Aug 2011 Location: Sacramento, CA Posts: 218	I'm lazy so here is a cut and paste I found awhile ago on CV carb tuning. George (original poster) is working on 150 CC scooters which share the same power plant/carb as your Coolster. How's everyone doing ? There are a few carb tuning threads out there , but I'd like to post a quick carb tuning tutorial. First here is a pic (Picture #1) of the most common unsealed150cc gy6 carb. This is your typical 24mm keihin carb. Is this a copy or is this the real deal ? To be honest we just dont know for sure. The copies have become so good that not only do they look good , but the work just as good also. Here is a pic of the idle adjustment screw. (Picture #2) And here is a pic of the air fuel adjustment screw. (Picture #3) This tutorial is focused of tuning your carb with the air fuel and idle screw. Remember jetting may also need to be considered , along with vacuum leaks , if you cannot get the carb tuned correctly with these steps. The first thing you want to do is start your scoot , after your scoot is warmed up and the autochoke closes of the extra fuel , you will next turn the idle screw clockwise so your rpms are a little higher then recomened, which would be anywhere from 1800-2000 rpms. Now what you want to do is turn the air fuel screw clockwise until the rpms begin to drop off. Next turn the air fuel screw counter clockwise until you get you highest rpms possible " be very careful , if your rpms begin to rise too high the clutch may start to engage , and the scoot could take off on you !! " to avoid this , you can back the idle screw off some by turning it counter clockwise dropping the rpms back down near 2000 , then you can continue turning the air fuel screw to obtain the highest rpm possible. Remember you only need to back the idle screw down IF you notice the rpms getting too high and the clutch wanting to engage. Finally , after obtaining the highest rpm with the air fuel screw , you will now want to use the idle screw to set the idle rpm back down to around 1700 . After you have the carb tuned in properly, you may need to adjust the air fuel screw according to the weather. For instance , if the temp drops 30+ degrees , you may need to retune the carb due to the cooler dense air. These setups are very touchy when it comes to the drop in temps from season to season. Hope this helps. Thanks , George Attached Images __________________ 1986 TT350, 2002 Grizzly 660, 2009 TR125 and two 2015 Kandi 150cc Quads.
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