High Idle coming down the mountain

fishtank · Feb 15, 2011

I seem to be getting a high idle at the end of a days riding. Most noticeable coming home on the trail when I back off the throttle it will still sit around 5000-5500 rpms and I can only seem to get it to drop down by applying the brakes.

We thought it might be moisture in the fuel so I added some stuff to clear that out. It seemed to maybe work a little bit but that might have been my imagination.

What else could it be? Sticky/frozen throttle cable?

Ghuds · Mar 3, 2011

Do you have a left hand throttle?

winter brew · Mar 3, 2011

Is the sled still moving and the clutch engaged?

KMMAC · Mar 3, 2011

fishtank said:
I seem to be getting a high idle at the end of a days riding. Most noticeable coming home on the trail when I back off the throttle it will still sit around 5000-5500 rpms and I can only seem to get it to drop down by applying the brakes.

We thought it might be moisture in the fuel so I added some stuff to clear that out. It seemed to maybe work a little bit but that might have been my imagination.

What else could it be? Sticky/frozen throttle cable?

Have you checked the reeds? Is it efi or carb? Check the fuel pump, lines, even though it seems like it's an end of the day problem, it could be that you may not notice it until the end of the day.

Arctic Thunder · Mar 3, 2011

Possible worn or sticky injectors.

I know a diesel when you get out of it and the R's hang a bit it can be caused by worn or sticking injectors.

Just a thought.

Otherwise an air leak or something. Possibly.

Thunder

Devilmanak · Mar 5, 2011

Probably just the clutches. Mine does it and I like it, I noticed it more after cranking up the secondary spring. It has engine braking through the clutches when going downhill. Try to find out if the clutches are making it idle high or if the engine itself is doing it.
Chris

PowderCrew · Mar 7, 2011

I tend to second the clutches...

Devilmanak · Mar 9, 2011

I took my "new" 06 Sno Pro Mod with a 150 track for a ride the other day, talk about engine compression braking! It will just about throw you over the bars if you are not careful, lol.

fishtank · Apr 19, 2011

Sorry for the late reply, just got back from a few weeks off.

It doesnt seem like the clutches. Im almost certain its the engine. Sometimes I will release the throttle and it will just keep cruising along at the 5000-5500 rpm I mentioned above even when the trail goes flat.

Grabbing the brakes and forcing the track/drive train to stop seems to get the idle back down to 2500 or whatever it idles at.

I tried some de-icer in the fuel at one point. It seemed to help a little bit but again at the end of the day it would do the same thing.

Someone else mentioned gummed carbs? Can I run Seafoam through this engine without having any difficulties? Almost the end of the season, probably only got 1 or 2 rides left in me and dont wanna have to pull the carbs out to clean them until I have more time.

Or just a sticky throttle cable?

fishtank · Apr 24, 2011

So I ran some Sea Foam in the fuel but it didnt seem to make much difference.

Seems to have trouble when I re-start it on the mountain after being left for 45-60 mins. The engine will die and bog out unless I keep my finger on the throttle and keep the revs at ~3000 rpm for about 30-45 seconds and then it idles ok.

Once riding the revs like to sit at 5000. If I jam on the brakes and lock up the track, the revs will drop down to ~3000 again but then if I let off the brakes they go back up to 5000.

Not sure if this is a sticky clutch or not. Maybe, but if I fully stop the track/sled and then the revs still sometimes jump back up to 5000 or so.

TPS perhaps?

Is 3000-3500 rpm high for an idle?

diggerdown · Apr 24, 2011

I wonder if you air temp sensor is leaning the fuel out too much. Usually high idle is a lean condition. I think if you uplug it the mixture will go rich but it would be a way to check it.

fishtank · Jun 9, 2011

Fixed.....sorta

So I ended up just taking this in and had a bit of a once over by the shop. Turns out the throttle cable was incorrectly set by someone (funny that the last place to do any sort of engine work was the same shop) unless this setting could somehow change over time???

They also replaced the belt (I thought you just ran them until they blew, lol), cleaned the fuel lines out and purged the carbs. They also pulled the primary clutch and replaced the rollers saying they were worn.

Anyway, high idle is gone. Much better engine compression braking when coming down a hill from a climb, so Im happy there. High idle issue must have been the clutch being stuck or something.

But the idle/stalling thing is still there and its possibly worse than before.

When starting from cold I have to leave the choke on for a good few mins and even once engine is completely warmed up it will idle right down to under 1000rpms and eventually stall if I dont keep the throttle on.

Its not a huge issue I suppose (unless these are symptoms of something sinister!?!). Id rather it not idle so high and just have to keep my finger close to the throttle when idling.

Any thoughts / suggestions?

WyoBoy1000 · Jun 9, 2011

Get it nice and warm, then adjust the idle. I would also check to see that both carbs are adjusted the same.

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High Idle coming down the mountain

fishtank

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Ghuds

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winter brew

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KMMAC

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Arctic Thunder

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Devilmanak

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PowderCrew

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Devilmanak

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fishtank

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fishtank

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