2000 Formula Z 600 idle issue - Snowmobile Forum: Your #1 Snowmobile Forum

goober2 · 01-13-2013, 08:55 PM

My skidoo runs fantastic but won't idle (dies out). I'm stumped on this one.
I've cleaned the carbs 3 times, replaced the pilot jets (37.5) and main jet (280) with stock parts, replaced the carb boots and set the idle and air screws to spec. Adjusting the air screw does nothing to help and I've even inserted larger pilot jets (40) with no luck. Compression is 135lbs in both cylinders (checked warm with throttle held wide open). Any suggestions?

goober2 · 01-13-2013, 09:07 PM

Additional notes: Carb slide height has been adjusted (calibrated with 7/32" drill bit). I cleaned the carbs with carb cleaner and compressed air. Throttle response is good from low to high.

minisrint521 · 01-13-2013, 09:27 PM

R those round or flat slide carbs? Check your reeds?Has 2 b an air leak somewhere if your air screw has no effect.Plug gap around .020?...

goober2 · 01-13-2013, 09:34 PM

Quote:

Originally Posted by minisrint521

R those round or flat slide carbs?

round carbs

goober2 · 01-13-2013, 09:41 PM

Quote:

Originally Posted by minisrint521

R those round or flat slide carbs? Check your reeds?Has 2 b an air leak somewhere if your air screw has no effect.Plug gap around .020?...

Reeds look good. Did not gap new plugs. Would it make that big a difference?

**RJ Gleason** · 01-14-2013, 04:57 AM

Yes it can make a difference. New plugs are supposed to be gapped already, but I have found many right out of the box to be way off [usually over sized].
Minimum gap for a CDI system would be 0.025.

**smallengineguy** · 01-14-2013, 06:21 AM

Where can you get it to idle (what RPM)? If the center seal is gone or letting pressure leak between the 2 cylinders on the crank, it won't idle below 3000RPM or so.

goober2 · 01-14-2013, 08:13 AM

Quote:

Originally Posted by smallengineguy

Where can you get it to idle (what RPM)? If the center seal is gone or letting pressure leak between the 2 cylinders on the crank, it won't idle below 3000RPM or so.

With throttle partially engaged, I can get it to idle at 2000 rpms.

goober2 · 01-14-2013, 08:18 AM

Quote:

Originally Posted by RJ Gleason

Yes it can make a difference. New plugs are supposed to be gapped already, but I have found many right out of the box to be way off [usually over sized].
Minimum gap for a CDI system would be 0.025.

Thanks. I'll check gap and report on progress.

goober2 · 01-14-2013, 07:43 PM

Quote:

Originally Posted by goober2

Thanks. I'll check gap and report on progress.

Gap has been adjusted with new plugs. Same problem.
I also cleaned the rave exhaust valves (found them to be fairly wet with gas). Is this normal?

**smallengineguy** · 01-15-2013, 06:20 AM

If you haven't run it a lot, then yes.

edge800ves · 01-15-2013, 10:53 AM

Ive never owned a Cat, but I have a 90 indy 500 with mikuni round carbs that had a similar issue, if the carb is similar to what I had my problem was in the float bowl, just a bit of varnish like gas residue restricting my floats from moving properly on the posts the bowl rides up and down on. Its something to check anyway

edge800ves · 01-15-2013, 03:30 PM

another thought, your choke could be stuck.

goober2 · 01-16-2013, 08:37 PM

Quote:

Originally Posted by edge800ves

another thought, your choke could be stuck.

Thanks, I'll double check choke and float bowl. I've also ordered new reed valves (what the heck).

goober2 · 01-19-2013, 05:19 PM

V Force reeds installed and same problem.

So, I took out both choke cables from carb ran the sled. It idled very smoothly but at high rpms.

After tinkering with choke cables and adding slack ...voila! Problem solved. Strange how the cables needed adjustment, but it now idles like a new machine.

Thanks to all for your tips and advice.

cheers!