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1999 300 TRX 4x4 carb question

955 Views 4 Replies 3 Participants Last post by  Goober
I tried looking for this info first before posting this question, and could not find it. Im sure its here somewhere, but I just couldn't find it, and I do apologize if this is the 300 time this has been asked.

My quad runs great around where I hunt in CA. 3500 feet or less, but when I go out of state and get above 6000 feet, she is obviously a little rich and will stall out about 20 seconds after I let off the gas. Starts back up, and runs though.

So my question is, how do I find out what size jets to get so that my carb will be happy?
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Here is a picture from my Haynes Workshop Manual, your issue is a simple fix by means of adjusting the pilot screw mixture on the underside of the carb.

At idle simply screw in the pilot screw until it is LIGHTLY seated, don’t wind it in hard as it will damgebthe tip. Back the screw out according the manual reference or until it starts to run correctly.

Correct fuel mixture is identified by looking at the spark plug colour, your after a nice beige/Tan/Tea type colour on the tip of the spark plug.

Hope that helps

Edit: Just realised the manual reference says ‘turns in’ from standard setting. Standard setting is 2 1/4 to 2 1/2 turns out.


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No problem, report back and let us know how you get on after making adjustments.
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