Motorcycle Repair Questions? Ask a Mechanic ASAP
The choke cables need to be synchronized when adjusted.
First, make sure choke is off. Pull up the rubber boots on choke cables where they attach to the carb bodies.
Loosen the adjuster jam nuts.
Turn the adjuster up until you no longer have cable play, then turn it down one turn. Do the same to the other carb. Tighten the jam nuts and put the boots back down.
As long as your cables are good, that should be all that is needed. The choke lever should have off (down) a middle and a full choke (up) setting.
what do you mean by cable play
When you turn down the adjuster at the base of the cable where it goes into the carb body, the cable housing will have freeplay. If you back the adjuster out (up) you will feel the play get less and less until gone. At that point the choke plunger is starting to open in the carb. You need to turn it down 1 turn from there so there is freeplay in the cable or the choke will be on a little all of the time.
When done, each cable with have freeplay at the carb and the lever will have about 1/8" freeplay. Give me a moment and I'll post a diagram of those things for you.
A is the jam nut, B is the adjuster.
This is the final result showing the freeplay at the lever. If you have a single carb machine, that is the only measurement you need to achieve. On a 2 or 3 carb motor, each cable must be adjusted so they open the same.
If there is not enough freeplay, the full choke position will not work and the sled won't start when cold.
Does all of that make sense??
yes, what is the right way to set the idle when i am done
Do you have a two or three carbs?
If nobody has messed with them, you can just turn the idle screws all the same amount to raise or lower the idle. If the carbs have been off, or someone has cranked in one of the screws but not the others, then the carbs need to be synchronized and all of the idle screws reset. Would you like that information?
Before you start, be sure the carbs are on in the correct order. Most Polaris 3 cylinder motors have different carb jetting for each cylinder. Another note is that there is a safety switch on your throttle lever. When the cable play is being adjusted, the engine may cut out until you are finished. You can always unplug the throttle safety switch until you are done.
Snowmobile carburetor synchronization:
This is a very fast and effective way to synchronize VM style snowmobile carbs after they have been removed for cleaning or to replace the throttle cable. It can be done with minimal tools.
You will need to access the intake side of the carbs, so pull the airbox boots out of the way. On some models there is no room to do that, so follow this process before you install the carbs. Just remember to prop them up so there is no tension on the cables.
1. Back out the idle screws.
2. Turn down the cable adjusters so the slides bottom out. Verify that all slides bottom out when you let off the throttle. If any don’t, there is a problem in your cables. Replace the cable and proceed.
3. Turn up the cable adjuster on one carb until you feel the slide move. Turn it down ½ turn and repeat for each carb.
4. Turn in an idle screw until you feel it just touch the slide. Putting your finger on the slide will help. Repeat for the other carbs. Now turn in each screw three turns. Remember that from now on, anytime you want to adjust the idle, all screws must be turned in or out the exact same amount.
5. Open the throttle lever and put your finger or a straight edge in the carb bore. Hold the throttle open so that the bottom of the slide is even with the top of the bore in the carb. Hold the throttle there and check the other carbs. Adjust the cable adjuster at the top of each carb until all are flush. Open and close the throttle several times and double check. Remember that from now on, to adjust cable freeplay, all adjusters must be moved the exact same amount.
6. Check your throttle cable freeplay at the throttle lever and compare to the factory specifications. Adjust the cable adjusters as needed to reach this amount.
7. Start and run the machine. Adjust the idle as needed and then check the throttle freeplay. You are done.
Now the carbs can be fine tuned with a synchronization gauge if you wish. You should find that they are within specs if you have done the job correctly. My method works because the slides and the carb bodies are machined parts and are virtually identical from one to another.
The air screws set at about 1.5 turns out.
Throttle lever freeplay on your model is .010" - .030"
Do you need more information?
If any of that doesn't make sense, let me know.
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