# carb tuning after snorkel



## rubiconrider

well i built a snorkel for my 07 rubicon a while back am im not sure its running quite right. it doesent sputter or hesitate or anything, but i think it lost a bit of power. im not sure because i might just be paranoid. the only thing really noticabe is when im going at high speeds in 5th gear and let off the throttle it begins to engine brake(which is normal). it pops and kinda backfires, nothing too loud or anything, as it engine brakes. it has always done this but now when you go to hit the throttle again it dies out for a second and then comes back and begins accelerating. its got an hmf utilty series on it, and im not sure what its jetted at because it was on there when i bough it at. ill post a pic of the spark plug too. 

any help on what to do would be great.


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## rubiconrider

i didnt know how bad this pic was till i got it on my computer. ill get a better one tomorrow.


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## Bootlegger

well if its popping and cracking its lean....if it falls on its face its rich. Is the tip of the plug white? I can't tell in the pic. Even if its lean some will still be black around the edges like that. If I was you I would go up one size and see how it does. if its worse...then go back down one. Jetting can be a pain....that is tricking looking plug...lol


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## rubiconrider

i know right??? kinda pissin me off trying to diagnose the thing. its not white, its a lightish tan color. but its almost sooty around the edges. ill get a better pic on here tommorow evening if you wanna look at it. thanks for the help.


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## rubiconrider

oh and also could this be helped by adjusting the air fuel screw? im just thinking it might not be getting enough air cuz of the snork.


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## Bootlegger

Not really...here is how your carb works

1/8-1/4 is your pilot jet
1/4-3/4 is your needle
3/4-WOT is your main jet

you want a light brown tan color...it maybe a little rich. Try going down one jet size. Are you using a Dynojet kit??

Ok..I am on my big computer now..I can see it better. It looks rich. Go down one size and see what it does. Also if you have a Dynojet kit...what notch is the needle clip on?


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## rubiconrider

no jet kit here. probably gonne pick one up soon. but ya ill see if our small engine place here can get me some jets and ill try going down a size. ill still post a better pic of the plug tonight.


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## Bootlegger

To be honest...you will be a LOT better off to just get a jet kit.


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## rubiconrider

ya thats what i figured. people say there a waste of money but im sure they're not. one thing i like is the adjustable needle it comes with, thats a nice adjustment to have. 

here is a better pic. ita a golden brown on top and black on the lower part.


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## Bootlegger

NO...a Dynojet kit Is the Way to go


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## Guest

If you are serious about getting the mixture correct get an air fuel gauge kit. You will need to weld in an 02 sensor bung to your exhaust as well. It is a lot more work up front but the mixture will be on when you are done. I got mine from hunterworks.com but you can get them elsewhere. Mine is a tool not a permanent gauge so I install it-tune it- remove it. Will work on any motor and is great for use with fuel injection controllers as well. 12.5 to 13.5 ration is where you want to be.


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## phreebsd

we just ordered a jet kit for clay's vinson. was $53.28 to the door!
from mudthrowers


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## jackg3

ive been struggling to get my mixture right... if im runnng too rich can i just go down a notch on my needles to match the jets or do i have to go down on the jets too??


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