choke adjust question - Snowmobile Forum: Your #1 Snowmobile Forum

Ad's Cat · 04-29-2008, 06:26 PM

Hi all, so i started workin on my wifes sled, a 97 xc 600. Just bought it this year and it was real hard to start all season. Figured i'd start with a choke adjustment. Had to replace the slider inside the switch box that holds the three cables. It was bent and jamming. The switch was tight too, no free play so i went ahead and loosened all the adjusters. Did as per the manual, pretty simple but i ran into a snag. Two of the adjusters seemed to set up easy but the third, well...i got my 1/8 to 1/4 inch of free play with the adjuster barely turned down. I couldn't lift the switch because it kept the line so tight. This ever happen to anyone? I kept turning it down until i saw the switch pop out a little more (prob mor like 1/4"). The switch feels a lot better now and the machine fired right up, 1 pull, its never done that, and kept running off choke once it warmed up. Now, should i be worried? 2 chokes set up at 1/8 and one at 1/4? All three cylinders fired up btw.
thanks

Adam

**RJ Gleason** · 04-30-2008, 04:43 AM

That one was probably stuck in the bore before and just popped loose.
Did you actually remove them from the carbs to check this, or just try to adjust them?

**smallengineguy** · 04-30-2008, 05:50 AM

Remove that one plunger and clean it and the bore it goes into.

Ad's Cat · 04-30-2008, 06:15 AM

Thanks guys, everything was removed and cleaned before the adjustment. Before i changed the jammed slider, i had just tried an adjustment. The slider would "pop" out in jerks instead of a smooth slide so i took everything out. After i reassembled, it was a smooth adjustment. Guess i'll pull them all again just to make sure. I'll take a closer look too, make sure nothing is catching.

Thanks

Ad

BC_Dan · 04-30-2008, 10:57 AM

As long as the plunger is seating when the choke is off and it starts first pull, the difference in adjustment won't hurt anything. If the plunger isn't seating, that cylinder will be running a bit rich, your fuel mileage will suffer. Chokes on mikuni carbs really aren't "chokes"; they are enrichment circuits. If they are not adjusted exactly right, the fuel/air ratio will be a little off for starting from cylinder to cylinder, but if it starts easily, that is unimportant as long as the plunger stops the flow of extra fuel when the lever is off. It's nice to have 'em start first pull

Ad's Cat · 04-30-2008, 11:31 AM

Thanks for the advice, any way to tell if the plunger is seating properly. Probably is since i was able to take it to zero clearance right? ...and once it warmed up i took the choke off and it ran more smooth. ALthough if the other two are proper then that would explain it. It was very nice to have the one pull start. Course i'll try it tonight again, and prob the next day too

BTW how long can you run the engine for in the summer with no snow to cool.

Ad

BC_Dan · 04-30-2008, 10:14 PM

if you have an open plunger, that cylinder's plug will foul or be a lot blacker than the other plug(s).

When I run my sleds in the summer (if I didn't fog 'em), I let 'em run until I can feel heat in the heat exchangers. At an idle, that is 10 minutes, minimum, to get the system good and warm. A warm system is necessary to evaporate any condensation that forms in the crankcaase. Starting and not letting warming to operating temperature can cause a lot of condensation and can rust bearings. You won't want to run it until the idiot light comes on... some of those come on just after you melt a piston