Strange idle when coming to a stop with my Viper

NB-NYTRO

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Oct 30, 2004
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Moncton
I finally had my sled out for the first good rip of the season. When I come to a stop now and let off the throttle. The sled revs up to 4,000rpms and then down to 3,000rpms and back up to 3,500rpms and then down to 1,800rpms. It didn't do this the other day when I had it around the yard. It seemed to start doing this after 10kms or so. Any ideas whats going on with this thing. It seemed to be burning way more gas the it should have. It burnt 28L in 80kms and that seems to be bad mileage. It also smokes more then usual. It seemed to work good overall. Any ideas whats going on with the machine ?
 
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The mileage is due to the type of snow you are running in right now.. not packed and very fluffy! Once the trails are done up right, you should get alot more. The up and down RPM's at idle???
 
Yeah we ran towards St. Antoine from Magnetic Hill. It was kind of rough in some spots. I will have to check it into the dealer is problems persist with the idle situation. Its smokes like crazy as well. Maybe it will straighten its self out. What would cause the strange rpms when the throttle is at idle ?
 
What is happening is throttle hang and very common I guess. I just posted the question a while back and got two ways around the problem.

1) is the bandaid lower your idle to 1400 rpms

2) is the proper way and that is adjust the fuel screw and richen it up a tiny bit. That is underneath the carb and sort of a PITA to get at unless you have been in there before and know what your doing.

I lowerd my idle and it fixed it for now, in the spring I'll adjust the fuel screw and raise my idle back to 1800 like it should be.
 
This is the first time mine has ever done it. It never did it once last year. It must be the way its set from the dealer from when the carbs were cleaned.
 
Yep that would do it, I ahd mine cleaned this year and it started doing it. If you do a search for my old post I think it was MrSled that descibed how to fix, the fuel screw is off 1/4 to a 1/2 turn. Till then lower the idle and your golden.
 
Are there any long term side effects to have the fuel screw off a 1/4 to a half turn ? She seems to be pulling real good. Thanks for the reply.
 
it wont hurt it if the fuel screws are off a little bit like that, it just has that annoying high, erratic idle. If you have to give it a quick shot of the choke to get the rpms down, you know that your fuel screws need to be opened up a little bit
 
idle

My buddies Viper had an irratic idle like that. Turned out to be a carb boot that was not on all the way. Make sure all the boots are secure to the carbs, check carb to intake clamps also.

good luck.
 
Thanks for the replys. I will check out the boots and so forth. Does anyone know what the fuel screw should be set at ? I have feeling I have a loose boot. It didn't do that the first day I had it around the yard. It started doing it after about 6 kms on the trail.
 
I called my dealer. He said it may be ice in the carbs and the stuff that has already been mentioned. I will have to check it out. Anyone else have any more tips on this idle problem ?
 


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