03 Rx-1 High Idle won't come down

[rgextreme1998]

Hi, I've read alot about others with this problem but still can't seem to fix it. When it is cold, it idles about 1000 rpms. Then when you blip the gas or take it for a sping it won't come down below 2500-3000 rpms. There is also popping i hear from the exhaust when it is running high. Then, when I turn it off, it backfires once. Everytime pretty much. It has mad power when driving hitting it and stuff, no bog or anything. Nice throttle response. BTW, at high idle, by doing the "choke" lever, rpm increases.

I have heard pilot jets, pilot jets are clogged. So, I took the carbs apart and they were all clean. yes, i ran a wire through the small holes. So, then i put it back together. Same exact symptoms. So I figure plugs. So i changed the plugs. And I put a couple gallons of new gas in it. Not sure where to go from here. I have heard TPS sensor as well.

The history of the sled this fall is that I ran it around a few miles in light snow and it ran fine - outside temp was about 20-30 F. Now it is about 10 degrees Farenheight and has this problem. Not sure if there is causation there.

I hate to take it to the dealer but I'm running out of options.

The sled has 2036 miles on it. I got it this fall, not sure of the history, but it was super clean, almost new looking. I changed the oil, that's about it.

This is my first four stroke so I'm a little lost!

Appreciate your responses!

Rg

 

[kinger]

Is your throttle cable free play adjusted correctly?

Its the exact same symptoms of a clogged pilot jet, did you look through each jet into a light to make sure you can see all the way through? Also how did the float bowls look? If there is varnish in the system they will plug back up almost instantly.

The symptons indicate its REALLY lean the popping and stuff and when you richen it up it actually increases RPM.

#1 make sure those carbs are clean

#2 check for leaky carb boots or other ways air is getting into the engine behind the carbs (spray ether around the area and if the engine revs you found your leak)

Report back. Thanks

 

[rgextreme1998]

Is your throttle cable free play adjusted correctly?

Its the exact same symptoms of a clogged pilot jet, did you look through each jet into a light to make sure you can see all the way through? Also how did the float bowls look? If there is varnish in the system they will plug back up almost instantly.

The symptons indicate its REALLY lean the popping and stuff and when you richen it up it actually increases RPM.

#1 make sure those carbs are clean

#2 check for leaky carb boots or other ways air is getting into the engine behind the carbs (spray ether around the area and if the engine revs you found your leak)

Report back. Thanks

The throttle free play was a little tight so I fixed that. However, the problem persisted. I let it warm up for a awhile idleing and it would barely idle. Then took it for a ride and it had the same symtoms - high idle, not coming down. So I adjusted the idle screw to have it idle at 1100. Then took it for a couple laps. And it now it DOES come down after riding. It DOES take about 10 seconds or so but it does eventually come back to 1100. 1100 seems a little slow, get a lot of rattling - I know that's normal but I'm willing to live with that. I tried to bring it up a bit to 1500 or so but then i ran into the same high idle problem. So.... not sure if i really fixed it but at least it's rideable now. I don't have any ether. I suppose I could use wd 40? I'll probably check the TPS when my electrician has a chance (my dad). thanks for your help. I dunno, i think i still have a problem, let me know.
rg

 

[aVenture]

How much turns on the PMS screws ?
..you can crank open a 1/4 - 1/2 on each to troubleshoot the pilot circuit.

 

[jsjk-4-stroke]

once you take carbs off & put back on you are out of sinc , mine use to rattle like you have once i sinc the idle is fine & no noise.
i took my wifes vector carbs off this year because of high idle , staying up, took apart , everything was clean , put them back on sinc was way off , also i set fuel screws 2 1/2 out , sinced carbs , idle comes right back to normal. hope this helps. if after this dose not work you may have bumped tps switch do a search on tps . let us know

 

[aVenture]

also i set fuel screws 2 1/2 out

I recorded original settings at first oportunity on my machine & always resetted to those after a clean-up; without mixing PMS screws. Always thought that this setting was mainly depending on the cut of the tiny conduit that goes to the carb corp & maybe the needle of the screw itself. My lowest setting is 1.90 & max is 2.30 turn from seat... Gen-120. If i'd had to go more or less fuel for some reason, i'd start from these base settings i have recorded which comes from the factory test bench.

Someone with better theory, please educate me.

 

[bdm]

Your symptoms perfectly describe my situation when I did not get the airbox perfectly seated. I also had clogged pilots when I got my sled new. Sounds like the typical things are already mentioned by others above, to summarize what I did:

-clean carbs

-run a wire through pilot jets to make sure that they are clear

-check throttle cable free play

-make sure that all airbox boots are perfectly seated

-sync carbs

 

[rxrider]

You have is a lean condition at idle.
Where's your pilot screws at?
If they are still at stock settings they can be all over the place.
Adjust them to 2 turns out from lightly seated, if problem is not fixed try to back them out another half turn, and run it again.

 

[rgextreme1998]

carb synching

When you say synch the carbs you mean with the manometer or similar? I see alot of links out there. What is the easiest/cheapest?

thanks everyone for your advice. Time to go to the garage!

 

[rxrider]

I like the Morgan Carb Tune Pro, very easy to use and not that costly either.

http://www.carbtune.com/

 

[grader]

check the diaphram springs in the top of the carbs. previous owner may have installed holzman aftermarket springs. these are colered to identify strength, eg. green, red, blue, yellow. stock springs are silver metal color. all the holzman springs are weaker than stock to allow slides to open easier with less vacuum. if used with a stock airbox they can hold up the slides, causing the high idle problems. you only have to check one carb by removing the cap (2 screws) but watch for a small o ring that is under the cap at the outside edge, dont drop it.

 

[rgextreme1998]

check the diaphram springs in the top of the carbs. previous owner may have installed holzman aftermarket springs. these are colered to identify strength, eg. green, red, blue, yellow. stock springs are silver metal color. all the holzman springs are weaker than stock to allow slides to open easier with less vacuum. if used with a stock airbox they can hold up the slides, causing the high idle problems. you only have to check one carb by removing the cap (2 screws) but watch for a small o ring that is under the cap at the outside edge, dont drop it.

I checked the springs, they look stock.

Ok guys, real dumb question. I have to take the float bowls off to get to the pilot screws??? thanks

 

[rxrider]

No you don't, but you have to loosen the carb rack from the intake tracts to get to the pilot screws, they are close to the intake tracts underneat the carb rack and virtually impossible to get at without taking the carb rack off, you may not need to unhook any fuel and waterlines

 

[rgextreme1998]

No you don't, but you have to loosen the carb rack from the intake tracts to get to the pilot screws, they are close to the intake tracts underneat the carb rack and virtually impossible to get at without taking the carb rack off, you may not need to unhook any fuel and waterlines

thanks! got it loosened. I do see one screw under there. I think it's the only one it could be? The manual just isn't clear as to where it is.

 

[aVenture]

Just aside the bowl heater.... you probably will disconnect that heater connector as well to be more comfortable. The screw is a flat head.

I recommend you to just remove the whole carb bank & work in peace on a better space. In that PMS hole.. (Pilot Mixture Screw) you will find:
1- the flat head screw that got a tiny needle
2- a spring
3- washer
4- o-ring

.. very easy to drop & loose some if you remove that spring loaded thing.

Remember... i would count the # of turn CW to reach the seat first, as for history... on each carb.