Carb Questions

[DTro]

2003 Polaris 500 Liquid Cooled

Late last year, I had a small piece of fuel line get lodged into the float pin and made the float stick. I tore the carbs apart and cleaned them out good. The problem was solved and I made sure that I kept the jets exactly where they were (number of turns).

I noticed however that reassembling it seemed to be idling too fast almost like it was running lean.

I guess it could’ve be a multitude of things that I might have disrupted in the process of pulling the carbs, maybe something as simple as the throttle position.

Is there a factory spec that I can find in which I’m assured that the carb jets are in the correct position, or is it fine tuned for each individual engine?

Is it acceptable to adjust something else externally to bring the idle down (Idle air mixture). I’ve read that this could be a band-aid that could lead to trouble in the future.

Also I noticed the rubber gasket that the carbs fit into on the engine side had some cracking, and I’ve read that an air leak there could cause a lean condition as well. But the crack looks like it had been there quite a while. Maybe I made it worse pulling the carbs off I guess, I don’t know.

I don’t have a tach, but if I blip the choke it sounds more like it should normally. Maybe a couple hundred RPM too high (just guessing by sound).

Suggestions?

[Macgyver55]

I would be very suspicious of the cracked intake boots. A vacuum leak there will only get worse and will risk further damage if it is running too lean at higher RPMs.

[Tyler23]

also a good way to find out if it is running lean is check the plugs if there still white on to bottom of the electrode its lean. if its nice and brown i think that means your running just right??

[broken_line]

yupp!

[slurpie]

If you think it is the cracked boot, have motor running and spray a small amount of carb cleaner on the crack. Not to much as it will cause the motor to idle up if it actually leaking.So to be safe you could also keep your hand on the kill switch. Make sure you only spray the boot area and not where it can get in the carb. I tnihk it is more likely that you twisted the throttle cable or it is stuck up a bit. I think that sled has round carbs. If you pulled (twisted) the main jet out you twist it back in tight. Same with the pilot jet, (little) jet next to main jet in a cavity takes little screwdriver to remove or install. Other than that i dont think there are any jets that you need to twist. Also if you twisted any settings on the outside of the carb then contact your polaris dealer and get the specs for the idle adjust screw. Sorry lots of little things that it could be.

[DTro]

see that is what I thought. The jets were screwed in tight so I didn't think I messed it up.

I didn't make any external adjustments.

I should replace the boot anyways I suppose. Just thought I'd see if it could be anything else or any other adjustments I should make.

Thanks for the ideas

[Deep_Sinker]

I'd check for leaks on the boots, but if you don't notice any obvious cracks you could try to adjust the fuel screws. I normally will seat the screws and then turn them back out 1.5 turns. See where it is running and tweak from there. Your manual should tell you what RPM for idle.

[DTro]

Thanks I'm going to be pulling it out of storage here probably in the next week or so.

I don't have a tach on it, so I'm just going by ear.

[jeffreyd]

the float did not get bent up a tad did it, or installed upside down?

[mudslinger64]

I'd check for leaks on the boots, but if you don't notice any obvious cracks you could try to adjust the fuel screws. I normally will seat the screws and then turn them back out 1.5 turns. See where it is running and tweak from there. Your manual should tell you what RPM for idle.

bingo,if you don't have any air leaks you will need to adjust your air screws.start at the 1.5 turns out and if it still idles high turn each one in 1/8th of a turn and keep doing that until you get to where you want it.when adjusting these it is the opposite of what you think,when you turn the screws in you are riching it,out you lean it.

[DTro]

cool thanks, I've heard that adjusting the screws could be masking a bigger problem, so I was a little hesitant to just go messing with them.

[mudslinger64]

once you get the adjustments right it should drop back down to an idle pretty quick and rev up without a bog,once it does and the rpm is not what you want then you will have to turn each one of the bigger idle screws not the air mixture screws you just adjusted in or out the same amount with each one until your idle is right.you also want to make sure each one of the slides open and close at the same time.when i would adjust them on my 900 triple i would use a 3/16 drill bit and set each slide so they would just scrape on the bit,make sure you do this when the carbs are on the motor,then check to make sure they are all start moving at the same time if they don't then adjust the cable on top of the carb that is starting to open last until they are the same.if you do this a couple times you will be able to do it in your sleep.if it is confusing let me know and i will try to walk you through it...

[DTro]

Just thought I would bump this one up. I finally went and bought a tach for my sled, and as expected it was idling at about 2400. Blip the choke and it backed down and ran perfect at 1600.

I checked for leaks at the carb boots and also crank shaft seal using the spray method. All was good.

Tore the carbs apart again then cleaned all the jets and whatnot.

Reinstalled and noticed that throttle position dealie (butterfly pulley thing) was not bottoming out against the stop when I let off the gas. So I made some adjustments there, but however in the process also discovered that the top adjusting nut on the throttle cable is stripped.

The funny thing is that it is running good now with the top nut not even threaded.

I imagine the only fix here is to replace the whole cable though huh??

[DTro]

This is what I'm talking about:

[pureinsanity]

Yes, replace the cable. Throttle cables often stretch out. I know I replaced mine every year or so on my dirt bike.

[DTro]

So I've out riding a bit in the past couple of days and something still doesn't seem right.

I'm leaning towards the throttle cable being the issue, especially since it is just bottomed out there and kind of wobbleing around (top adjusting nut not threaded).

As is, I don't seem to be getting quite the throttle response as I expect and could only top out at 64 on a packed trail.

Right now, it idles at about 1600, engages at about 4000 and tops out at about 7600. Does that seem right?

How hard is it to replace that cable assy? Looks like I need to tear into the steering to route the cable.

[Macgyver55]

First off is it the threads on the cable housing that are stripped or the nuts that thread on to it? The nuts can be replaced by taking the cable end off the carb and threading new ones on. If it is the cable, you could possibly get it to work by putting double nuts on it so they are gripping on a part of the threads that are not damaged, but still end up with the correct adjustment.

The wide open throttle is what is affected by this adjustment. What you need to do, is adjust it so that when the throttle lever is squeezed to the bar the carbs should be all the way open. Judging by the picture and where the nut is, you are probably only getting 3/4 or so.

I hope I'm clear enough on what I described, but if not ask more questions.

I want to be very clear as to make it a safe repair.

[DTro]

Thanks, unless the threads are tapered, I think it's the threaded portion and not the nut. I don't know for sure though. I just know that I cannot get it to grab and the threads look stripped towards the top.

Will the nut slip over the barrel at the end of the cable? I thought about trying to replace the nut, but it didn't look like it would slip off.

I'm going to dig into it a bit tonight when I get home.

[Macgyver55]

The nuts should slip over the cable end. If the old nuts are messed up, I'd try to cut them off as to not damage the threads any more while taking them off.

[DTro]

Well the nuts didn't slip off. I took the cable off and went to go get used/new one in Victoria. I guess the one I have was only used a couple of years and not very common. It's a single cable with no oil line.

Anyways, I ended up using lock washers and opening them up and using them as spacers.

Now that I played around with it a bit, I can tell I was having issues with the throttle safety switch on Sat. Actually I still am, so I might have to buy an new cable anyways. If I jiggle the throttle I can get it to kill.

I replaced the plugs and it ran really good tonight. However with all that said and done, I'm kind of back to square one, because now it won't idle down again unless I blip the choke.

[chasineyes]

Hello, I noticed on one of the carb questions that you talked about the air/fuel mixture screw. I'm guessing this is on the outside of the carb itself. What I"m finding currently on my 600 yamaha is that when it gets warmed up and I get in deep snow it bogs down at start and unless I pin it and get the RPMS over 6000 it just has no get up and go. I have checked the plugs and they are quite wet. That's leading me to believe it's running "rich". I did clean the carbs this fall and they seem to be working fine. I'm guessing this air/fuel adjustment will help with the bogging?

THanks a bunch!!!