Whizzer Carb Adjustment Screws

MoonKS

Member
Joined
Apr 4, 2008
Messages
170
Hi everyone,

I believe my Whizzer might be idling a bit high - I am looking at the adjustment screws on the carb and I am not sure what each one does...

I have attached a picture of the carb on my NE5 - I labeled one screw A and one B. What is the purpose of each one - I turned A counterclockwise a bit and it brought the idle down a bit....

I know one is for air mixture.... I am just trying to learn what each screw is responsible for and what the ramifications of adjusting them are (making too rich or too lean).

Thanks in advance!

Regards,

Matthew
 

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MoonKS

Member
Joined
Apr 4, 2008
Messages
170
And while I am on the subject - do I have to order the inline fuel filter for my NE5 from Whizzer or is there some alternative I can buy in my local autoparts store?

My Whizzer has just over 300 miles on her and the fuel filter is full of little black specks....
 
M

MotorbikeMike

Guest
22mm carb

HI Moon, the "A" screw jacks the slide up and down via a ramp cut in the side of the slide, this is Idle Speed Adjustment.

The smaller "B" screw is then an Idle Mixture Screw, which I beleive to be the air-bleed type, due to it being in the throat of the carb.

This would mean, preset idle with the speed screw, refine the mixture, reset speed to desired, and then refine mixture, if needed.

Mike
 

Quenton Guenther

Well-Known Member
Vendor
Joined
Aug 2, 2007
Messages
2,151
Hi MoonKS,
Mike is correct the air mixture adjustment screw is AIR on the 22 MM carburetor. Turning the idle mixture screw counter clockwise adds air [lean], normally the screw is 1 - 1/2 turns out. The best way to adjust the idle mixture screw is to start with a warm motor, adjust idle mixture for fastest idle and the adjust idle adjust screw to maintain an idle between 1200 and 2000 RPMs [don't lower idle to sound cool below 1200, because the motor is a "splash" system].
The 26 MM carburetor is just the opposite on the idle mixture adjustment because it is FUEL [not air], and turning the screw counter clockwise adds fuel [rich], and the normal setting is 1 turn out. The adjustment on the 22 MM has less effect than the 26 MM carburetor.
Have fun,
Quenton
 

MoonKS

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Joined
Apr 4, 2008
Messages
170
Hi Quenton - do you mean 1 to 1.5 turns or 1/2 to 1 turn.

And by turns do you mean a full 360 degrees or a 180 degrees?

Sorry for my lack of understanding....

Thanks,

Matthew
 

Quenton Guenther

Well-Known Member
Vendor
Joined
Aug 2, 2007
Messages
2,151
Hi Matthew,
Thanks for pointing out the error in my post. 1 and 1.5 turns out. One turn = 360 degrees.

Have fun,
Quenton
 

MoonKS

Member
Joined
Apr 4, 2008
Messages
170
Hi Quenton,

Thanks for the information! I adjusted the screw appropriately - I replaced my fuel filter with a better quality line from a Go-Kart/Lawn Mower repair shop - I found a clear filter but it was 1/4" - but I got some nice clamps from the shop that clamp tightly and there are no leaks.

Tuning my idle and air mixture - cleaning out the gas tank today - putting a new fuel filter on - putting the new Iridium plug in - she runs a lot nicer - surprising what some simple improvements and maintenance will accomplish!

Thanks,

Matthew
 

go-rebels

Member
Joined
Dec 16, 2008
Messages
194
Hi MoonKS,
Mike is correct the air mixture adjustment screw is AIR on the 22 MM carburetor. Turning the idle mixture screw counter clockwise adds air [lean], normally the screw is 1 - 1/2 turns out. The best way to adjust the idle mixture screw is to start with a warm motor, adjust idle mixture for fastest idle and the adjust idle adjust screw to maintain an idle between 1200 and 2000 RPMs [don't lower idle to sound cool below 1200, because the motor is a "splash" system].
The 26 MM carburetor is just the opposite on the idle mixture adjustment because it is FUEL [not air], and turning the screw counter clockwise adds fuel [rich], and the normal setting is 1 turn out. The adjustment on the 22 MM has less effect than the 26 MM carburetor.
Have fun,
Quenton

Thanks Quenton,

How do I know if I have a 22mm or 26mm carb? Also, for reference, which way do I turn the idle adjust screw to increase RPM (CW or CCW?)
 
M

MotorbikeMike

Guest
Carb 101 continues

Hi Go, well not much chance that you have a 26mm, it would be the 22mm as the 26's were pulled at Headquarters.

Mike
 
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