Hi Folks,

My first post here. Thanks for the forum.

A quick use of the search function got no direct hits on my question so I thought I'd post.

I just purchased my first sled (previously rode OPs (other peoples)); I bought a 2000 Arctic Cat Panther 550 with 2500 miles.

I am an experienced motorcycle mechanic, but 2 stroke motors and the snowmobile drive mechanism are kind of new to me.

History of the sled: 1st owner put the miles on it. 2nd owner from whom I bought it got it in 2005 and it mostly sat unused undercover. The machine is pretty clean.

My biggest issue is occasional failure of the motor to come up to full RPMs. This typically happens after the machine is warmed up, and I have just stopped or reversed, and then I can't get the RPMs over about 4K and the clutch won't engage below this engine speed. Plenty of smoke coming out when this happens so I think the oil injection is working ok. And it seems more likely to happen when the machine is facing uphill on a slope. After sitting and fiddling with the throttle for a while, sooner or later, the motor gets its juice back and runs fine again.

I suspect an intermittent fuel blockage (something sloshing around in the bottom of the gas tank occasionally blocking the fuel outlet), or a sticking carb float, or maybe something occasionally blocking a jet in one of the carbs. The fuel filter looks clean.

Before I start taking things apart to clean, inspect, and reassemble, I thought I'd ask if this a know problem that other's have experienced.

Thanks for any replies, and thanks for this forum.

Charlie in Vermont

Sounds like problem may be in carbs, given history of sitting for a while. Remove carbs, dismantle, and clean. MOPAR penetrating fluid from DODGE dealer excellent for this. Remove seat, drain old gas, add a bit of new gas, rinse and drain. Remove fuel line fron tank, both inside and out. Check filter on lines end in tank. replace if necessary. Replace fuel filter. Check pulse line is seated properly. Replace spark plugs. This takes care of the cheap and easy stuff, I think.

If problem still persists, cud be fuel pump. Hopefully you are now fixed or it starts getting expensive.(coils, cdi, stator).

Another thing check your ground wires. Check resistance on plug wires and caps, get a service manual, specs are in it.

This cud b a lot of things, but I am betting on carbs that have been sitting too long with old gas.

If u have exhaust off, check condition of pistons.

One last thing. Here is a website that will show you parts diagrams and numbers and prices of any parts you should need:

http://www.brownsleisureworld.com/

Hope something here helps. If not switch to a 4 Stroke Yammie., needs no work.

good luck
r

Thanks for repy and suggestions.
Working on it.
C

Taking the car5bs apart and cleaning everything is the first thing to do, especially with a sled that has been sitting, unused for an extended period of time. Always start the year with clean carbs and fresh fuel.

The engine in your sled is about as simple as they come, a basic piston port engine with no reeds or exhaust port modifier valves (APV in Cat speak). If it runs fine and then has periodic spark interruption, then there are a couple other things to check. The Throttle Safety Switch (TSS) system should be bypassed to test to see if that is causing your problem. When the TSS acts up it will cause an intermittent spark interruption. The system is designed to cut off the ignition at speeds approaching engagement RPM to prevent the engine from starting, or running, if the throttle valves (carb slides) are stuck open. Unplug the three prong connector near the base of the handle bars to disable the TSS, this will also disable the kill switch, and if that is the problem a typical fix is to replace the bushings on the throttle pivot pin.

It shouldn't be a stator issue because you are able to get the engine to rev up after playing with the throttle for a while. Rather than a blockage I am thinking that it is getting too much fuel in these situations and once it clears out the excess fuel it will rev up. This could be the result of dirty inlet needle and seats causing float bowls to over flow. it could also be the result of poor jetting set up and the current set up could be way to rich for the conditions you were riding in. Does the engine work better in cold temperatures? What do the spark plugs and piston wash look like?

Thanks for the replies Gents.
Turned out to be easy. Isopropyl in the gas tank and fresh gas. But the real culprit was a spark plug.
Sparkplug failure modes continue to amaze and frustrate me.
This one would run fine, then loose power, and then run okay again for a while. So I was running on 1.5 cylinders in effect.
New plugs, no more problem.

Thanks again!

Hey charlie what pat of Vt you in ? I am outside of Bennington.I have a 2000 550 and it is bulletproof.I did have a kink in a fuel line back when it was new and would burp all of a sudden first year I had it but cleared up since finding that.