Needle Jet Orientation Important?

S

Sxviper04JR

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Jan 5, 2016
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Rochester
I just purchased a 2004 SXViper S and it has 2600miles on it. I know the owner and have put a lot of these miles on the sled. I know it has only run once or twice in the last 2 years and decided to clean the carbs and go through the sled before riding it. Snowmobile fires up runs and idles- bogs a little bit when giving it throttle. Assuming this is due to needing to be cleaned up and have the fuel screw turned in and backed up 1 1/2 turns.

Once I was done cleaning this and started putting the carbs back together I noticed the needle jet has a groove on it and on the casting of the carb there is a small pin that looks to be pressed in and I am assuming that this is to keep that need jet in one position.
On all three of my carbs they rotate around the casting.
Does the orientation matter and if so do I have to push that pin in further?

Any help or suggestions would be greatly appreciated.

Thank you!
 

it does if its a hooded needle nozzle, meaning it has a hood which blocks air around the inlet where the needle goes down thru the carb. Some carbs use a hooded needle nozzle and some don't depending on the calibration, if its not hooded then it doesn't matter really as long as it fits all the way down in the carb, usually the pin must align to do so. If it is hooded it must be installed correctly or it will not work correctly.
 
I haven't heard of this term before. How can I tell if it is a hooded needle nozzle? I have the same exact carbs as the instructions that you created. ------ Carb cleaning 101 with pics by MrViper700
Hope that helps answer it.
 
thanks for the pic mac, the hooded nozzle is the one on the right, the one on left is non hooded and isn't critical for placement AS long as it fits all the way down in the carb, it should seat flush with the floor of the carb.
 
Thank you for the picture and explaining this. I am going to assume that mine is not hooded. I am not home in front of the jets now.
This is the picture from your carb cleaning 101. They are identical.
Main Jet Carb.PNG

This would be not hooded correct?
 
Not correct. The pencil is pointed at the opposite end of the nozzle in the above picture. Yes its true that the nozzle in a Yamaha is not hooded. The reason for hooded vs not hooded is the ability to create more or less vacum signal. If you had a hooded nossle it would be seen thru the carb intake where air pulls fuel up from the float bowl. Hooded noz creates more vacumn signal.
---mac---
 
Mac and MR. Viper thank you for the help on this.

Sorry for the lack of brain power- I have seen the hooded nozzle on several carbs before but from reading this previous statement I thought we were talking about the end of the nozzle in the float bowls.

Thanks again!
 
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