99 summit x 670 idle problems help

MSP381 · Dec 10, 2016

I purchased a 99x with 2800 miles and when I loaded it in it ran great other than when hitting throttle it dies but not stall completely. Seemed like the dess was loose. Once I jiggled it it seemed to run great. Sat for a month and tried running today in fresh powder.

Started today no issues when it started and when I went to take off same thing...wants to bog down. Tried adjusting key and no luck. Seems to run at high idle. It also seems like it wants to run good at maybe half throttle.

I'm new to doo and the dess key. Any ideas?

Also noticed the plug going into airbox was unplugged. Did not notice it when I bought it. What's it for...dpm??

What adjustments are made when running at seal level?

Skidoox · Dec 10, 2016

I would bet your computer is bad.
We had to replace 3 of them on 3 different 99 summits.

MSP381 · Dec 11, 2016

Any other ideas and how would I check to see if it's the computer

MSP381 · Dec 11, 2016

What is this plug for. Supposed to be plugged in? Still waiting for some feedback

MSP381 · Dec 11, 2016

It runs fine above 4K rpm and when letting off throttle wants to die flat below 4K. Also seems to idle at 3000. Initial start up idles fine until I start to crack throttle.

Any help??!

nuttyn01 · Dec 11, 2016

That sensor is the air box air temp sensor and yes it needs to be plugged in. The plug for it is laying above your DPM manifold in the picture.

MSP381 · Dec 12, 2016

It's plugged in but still runs the same. Any other thoughts?? Come on guys I know there is some thoughts from the field..

Skidoox · Dec 12, 2016

You need to find another 99 that you can swap the computer with to see if it is the problem.

olymon · Dec 12, 2016

You mentioned sea level. Was this set up for the mountains and now you are using it at sea level? Have you put in sea level jetting and clutching? Sounds like a pilot jet that is too small with a 3000 rpm idle.

Making JIS screws into junk

MSP381 · Dec 12, 2016

I believe the problem has been solved. When I bought it in the fall I was told it was jetted and clutched back to sea level. I believe it was not because this was a back up sled. I'm pulling carbs off tonight. Any ideas what jets are needed for 0-2000ft and clutch weights.

Thanks

MSP381 · Dec 12, 2016

The main jet is 350 on pto. Does this sound right for sea level? Can't seem to find anyything

summit800 · Dec 13, 2016

350/340 55 pilot , id run 340/330 55 pilot

eddy · Dec 13, 2016

Runs Bad

While you are in there replace (do not clean) the pilot jets with stock. The run issues described above are consistent with gummed up pilot jets. The stock jetting in all positions will work from sea level to 14K (assuming all else is stock). Stock clutching should not be far off either (again assuming all else is stock). Those machines ran well in the day and it should hold its own.

MSP381 · Dec 13, 2016

The pto side is not running all that great.

MSP381 · Dec 13, 2016

Do run 350/340
Or 340/330

summit800 · Dec 13, 2016

I ran the 340/330, I'd remove the carbs and clean them and blow them out with a air compressor,also check the fuel inlet needle valves

summit800 · Dec 14, 2016

also check the needle clip location , start in the center position ,but you will probley end up in the the one above center position

summit800 · Dec 14, 2016

also check the needle clip location , start in the center position ,but you will probley end up in the the one above center position, the higher up the clip the leaner it gets

MSP381 · Dec 14, 2016

It needs crank seal replaced on pto side. Do I have to spit case to do this? Tried all above listed. Sprayed ether on pto side and rpms increased. Instructions on changing crank seal??

eddy · Dec 14, 2016

Crank Seals

Well, in that case until the bottom end is freshened up: Nothing else will solve the issue as you have an air leak leaning everything out.

99 summit x 670 idle problems help

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