How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ski Doctor Your Own Question
Ski Doctor
Ski Doctor, powersports repair specialist
Category: Motorcycle
Satisfied Customers: 818
Experience:  over a decade of double time experience, excellent electrical and mechanical diagnosis capabilties
Type Your Motorcycle Question Here...
Ski Doctor is online now
A new question is answered every 9 seconds

2000 polaris xpedtion 425...too rich..have schematic

Customer Question

2000 polaris xpedtion 425. trying to adjust carb... running way fast and too rich. have schematic and see large thumbscrew vertical under carb plus other screws but don't know what they all are... need description and location of all carb adjustments for this machine. idle , fuel etc.
Submitted: 7 years ago.
Category: Motorcycle
Expert:  Ski Doctor replied 7 years ago.

okay...there are several adjustments for the carb and i will tell you what they all are and do

1: underneath screw with black knob: this is your idle speed adjustment. by turning this screw clockwise, it will open the butterfly valve inside the carb, which will raise yoru idle speed up. to lower the idle speed, turn this counter-clockwise. turning this screw only raises and lowers your idle speed.

2: fuel mixture screw: on the very bottom facing up there is a screw that will control your fuel mixture. this is the fuel mixture screw. this should only be adjusted to fine tune your idle mixture and throttle response. if your throttle response is good, and you have no problems when you open the throttle do not mess with this screw. turning it clockwise will lean out the fuel mixture, and turning counter clockwise will richen your mixture. this screw is on the very bottom of the carb, near the engine side, facing directly up. you will need a very small screwdriver to adjust this on the carb, or a special carb adjustment screwdriver that has a ninety degree angle.

3: float bowl drain screw: the last screw on the float bowl, on the bottom is the fuel drain screw. this will drain all the fuel out of the float bowl on the carb. make sure your fuel is off at the fuel valve, or this will keep draining. this is used to empty the carb of fuel when you prep for storage.

are there any other questions or issues you have with your atv?

Customer: replied 7 years ago.
thanks! that explains my idle problem.. i have it all the way turned in clockwise (from the ground looking up) which based on your desc is raises the idle speed. not planning on adjusting the other screws but there seem to more a couple morethan i one fuel mixture screw you described based on the scematic ... what are they? you can see what i'm referring to at have to log in i think.
Expert:  Ski Doctor replied 7 years ago.

from your posted service manuel, on page C-13, i will describe the only screws that adjust something, and i will refrence the number and explain it's purpose.

#35: this is your idle speed screw. by adjusting this, your idle speedwill go up or down. this will only adjust your idle speed.

#34: this is your fuel mixture screw. this screw will control the amount of fuel that goes through the pilot jet circuit of the carb. the pilot circuit controls the fuel mixture at idle, and also fuel mixture from 0 to 1/3 throttle opening. the fuel mixture screw will also fine tune your throttle response.

#25: float bowl drain screw. this screw's only purpose is to drain the fuel from the carb. this is used only in prep for storage to empty the carb of all it's fuel.


which other screws are you refering to? these are the only screws that will change your idle/performance. there are no others that will effect the engine/fuel delivery.

if you believe i have helped, pleae click "ACCEPT" so i can get credit for your aide.

thanks! and pleae let me know which other screws you are tyaalking about if you have extras.

Ski Doctor and other Motorcycle Specialists are ready to help you
Customer: replied 7 years ago.
thanks ski doctor! great service and i'm glad i found you!
Expert:  Ski Doctor replied 7 years ago.

hey, i always appreciate a happy cistomer of this service!!

this post will remain open a few days with no activity on it, so please feel free to ask any more runability questions while it is still open(there wont be any more charges for extra questions)

so, feel free to ask anything! even about a different atv or motorcycle you have problems with.

thanks again!

please feel free to leave good feedback rating the accuracy of my answers and speed of response..

Customer: replied 7 years ago.

ok since you offered.... adjusted the idle down exactly as you described. got it to run very smooth (I think) a little faster than it should but workable...BUT it will run a while at idle 30 secs, a minute,,,or longer.. then do a swan dive and stall out. can recover it by pumping the throttle and/ or partial choking... any ideas? sticky float is all i could think of...


have a new plug, fuel filter, fresh gas and have run quite a bit of gum out through the carb.

Expert:  Ski Doctor replied 7 years ago.

well, sonce you have the unit at idle, and it stops running i have a feeling this is fuel related and not electrical or mechanical.

run your unit; then when it dies out again, remove your fuel cap from the gas tank very slowley. do this is a quite area. when you slowley open your fuel cap, do you ehar pressure escaping from the tank?

i am thinking you havea blocked fuel vent on the tank, so after it runs for a little bit, the fuel tank vapor locks, and prevents any fuel from leaving untill it sits and pressure relieves on its own.

so try this, where AFTER it dies, slowley remove the fuel tank cap and listen for pressure relief. it will sound like a quiet hissing noise. make sure you do it in a quiet area. this noise if you hear or not is very important

Customer: replied 7 years ago.
thanks for the tip. checked all my vent lines... tank, carb, and made sure they are clear... have decided its the carb and am going to take the bowl off and clean the float.etc ... wish me luck! never did it before!
Expert:  Ski Doctor replied 7 years ago.

dont worry. when you remove the carb, and then the float bowl, you will see that the mechanical design is very easy. just make sure you remove all the rubber parts before you spray them with chemicals that are unsafe for rubber, like carb cleaner. when you remove the fuel needle look at it closley for a worn groove on it. if the groove is very slight, then just clean the fuel needle and it will be fine. if the groove is pretty deep, you will needto replace the fuel needle. you may as well clean the jets too. they are brass and there are two of them. one is slip tall and skinny(pilot jet) and the other is short and fat(main jet) make sure you remove them before you spray carb cleaner through them. a common problem that people do is spray through them, and any debris that is in them will get lodged in the fuel passages.

please ask if you need advice ot tips. also, use grease on the o-riong for the float bowl when you reseal it to help seal it.

good luck!