polaris wont start or run right

[broken_line]

i just baught a polaris pro x 440 and it wont start for the life of me!!! i pour gas into the spark plug hols and it will pop a tiny bit but wont start running... when i did get it going and drove it around the yard a bit it was extremely boggy like i had to push it around the corners but once i hit around 5000 rpms the skis would come off the ground and i would be doing 50mph in no time.. when i slowed down it was boggy again untill it got around 5000 rpms then it took off.. get it back to the house and it idles only if im pushing the throttle a bit. and i have the screws in all the way for the idle adjustment.. i totally cleaned out the carbs new gas so im stumped and my arm is sore from an hour of pulling... also it seems the clutch kicks in at like 2000 rmps.

[hydro]

Sounds like carburation to me. Did you get the carbs back together right after you cleaned them? It is easy to put something back incorrectly, we all do it now and then. From your description, the low speed circuit is not functioning well. I suggest getting your hands on the factory service manual section on carbs (google it) and checking your work. Take the belt off to remove clutching from the equation and be sure things are running right. Did you make sure that the choke enrichment circuit is working correctly and not flooding the engine? Are the plugs wet or dry when you shut down as the engine bogs?

The comment that it runs hard from 5K up is the clue here. If the engine seems to perform correctly with the belt off then the carbs may not be the issue and the next step is to go through the clutch. On a race ready 440, you should see an engagement of about 5000 rpm to get into the powerband.

[MN Mike]

Does that carb have 2 jets inside the carb? The main jet and the low idle jet? To me it sounds like your low idle jet is plugged or your clutching / belt length is out of wack, make sure there isn't too much deflection on that belt.

Mike

[shawn1982]

This may sound very stupid but it happened to me one year and i couldnt figure it out for the life of me.... i had a polaris indy trail and first snow one year fired it up and took off....but it went south real fast and was very boggy. I found a mouse had built a nest in the air filter during the summer and the engine wasnt getting enough air....felt real stupid when the mechanic told me that but was glad it was and expensive fix....check it out that could be your problem

[Bigtom]

I would still think it would be a carb issue.

[broken_line]

4 hours latter i found out its the clutch. as soon as the motor would start it would start rubbing the belt and basically killing itself instantly. i took the belt off and, it idles at 1100rpms perfectly. revs up just like it should and idles fine again. i also found out that it will flood extremely easily if not choked right and if it back fires it blows the airbox apart.. can i safely (for the engines sake) remove the 2 trumpet like things in there?

idling at 1000 rmps (yes it is running) i was bored so i messed around with my flash and exposure time to get it still.

here it is with the engine off

what does this light mean?

[dan z]

your key was two poistion it can be in while it running. when that light is on you should be running prem gas.

[knoppers]

I believe all polaris require premium gas, or at least 90 octane, that light makes no sense to me, unless it has a plug that you can unplug that allows you to use lower grades of gas.

my cat F800 runs on 87 octane, but has a plug for using gas that has ethonal. must be the same type thing.

[Esox_Magnum]

The key has 2 positions one for regular gas the other for premium, somehow changes the reeds or something. I run both octains in my sled prem is better but all depends what I can get at the time, as long as it's non oxy.

[hydro]

Good to hear that the motor is running OK and you have found the clutch to be the issue! Take a close look at the speing to see if it is broken to start the troubleshooting. (Also, don't remove the air horns from your airbox, it will cause air flow and mixture problems)

On the subject of the light, remember you have a race sled with a small 440cc engine designed to be competitive while meeting class requirements. In order to maximize horsepower output, the factory has built in an ignition curve that maximizes the horsepower output by advancing the ignition timing. This advanced spark will generate more horsepower, but in doing so it requires a slower burning fuel to prevent detonation. That is what "Premium" fuel is and it's higher octane rating implies that the fuel burns at a slightly slower rate, making it more resistant to detonation. If your key switch has multiple fuel positions it allows you to run different ignition curves depending on what fuel is available. The light on the gauge will tell you what curve is invoked, and what fuel should be in the tank.

When you buy fuel, just make a habit of buying the 91 or higher octane "premium" to be sure that you minimize the possibility of running the switch in the wrong position and experiencing detonation (bad for the pistons!). Again, find a source for an owner's manual or factory service manual online to look up what Polaris says about fuel, then follow their directions not the advice you get on web forums. Unless the manufacturer specifies using non-oxygenated fuel only, don't get too hung up over the oxygenated (with ethanol added) or the "Non Oxy" fuel as your sled will likely run fine on either. If you have a choice, buy non oxygenated fuel if it makes you feel better.

Now if you really want to make that 440 scream, you can make some mods and run on E85, but that's another discussion........

[broken_line]

i found the culprit! the previous owner re built the motor and got a racing clutch kit for it. drove it for about 200 miles and didnt like the snap it had. and now i know why! he has the secondary clutch spring in the primary clutch and im guessing the primary in the secondary but i dont know how to get the secondary clutch apart. im guessing its the secondary spring as it looks about the same size as the one in my jag 340 and i can fullly compress it with my hands.

[broken_line]

heres the spring that was in the primary\

[2thepointsetters]

Most Polaris secondary springs I have seen had the tabs that go into the the helix for setting the pre-load.

[leech~~]

hydro, great info! I'm on my 3rd Polaris and have never heard of the two fuel key set thing. But, mine have always been 2 up's for ice fishing and not racing sleds!

[broken_line]

well... i got the clutch spring.. that didnt do it.. so i removed the heads.. and found melted pistons... they were running at about 60psi and 50... now what do i do?

[leech~~]

Didn't you say you just bought it? Didn't you start it when you bought it? Take the thing back to the SOB you got it from! Or start looking around for some new top end parts!

[broken_line]

yeah i drove the thing on the trialer.. the guy said it was rebult 300miles ago, needed a new clutch spring and a carb job. it idled like [PoorWordUsage]. but i cleaned the carbs, new plugs new gas.. yada yada new spring.. it will do about 79mph right now but the low end is horrible. the engine idles and top end are fine. low end is like a weedwacker motor..

pullstart side

left side

[MN Mike]

ARGH!!! That SUX !!

Doesn't help you much now but when I see people looking at the 'race sled' type of snowmobiles I say RUN! don't walk just RUN from them, you know they have been bought for 1 reason and that is to ride it like you stole it, the liquid cooled ones are WAY too high strung to be used by most people that are not mechanically inclined.

If you rebuild it, you better take a serious look at your carbs and see if they are stock, not just the main jets either, the whole works needs to be looked at, needles, seats, main jet, low idle jet.

Mike

[broken_line]

well i got it tore apart and ready to get honed out with new pistons and what not.. i got a lemon and im makin lemonade (:

[tonkapat]

That damage to the cylinder can't be honed out. You have nicasil cylinders that are expensive to replate. Find a 600 exhaust valve motor and put it in there. More power and reliability. I'd bet that buying a running motor is cheaper than the rebuild. Always,always,always do a compression test on any two stroke motor before you purchase.

[shortfatguy]

From what you described I would be willing to bet the guy didnt sell you that sled with a blown motor. There must have been something in the carb and thats why it wouldnt run right. Then it blew up while you were running it around trying to figure out why it wouldnt go. I cant see in the picture for sure but it looks like the piston scuffed the cylinder on 4 corners. That is indicative of a cold sieze. was the sled warmed up before you took off on it? If you dont allow it to warm up and take off the engine gets hot and the thermostat opens and runs really cold antifreeze into the jugs. this causes the cyl to shrink around a hot piston and gives you the tell tale 4 corner sieze. You should always let your machine warm up until the heat exchangers in the tunnel feel warm to the touch.

[MN Mike]

Ok, I'm confused..... is this a 440 fan or a 440 liquid?

Sorry, I'm not a Polaris person.

Mike

[leech~~]

It's got to be a Fan, no water jacket holes showing. I have fried many a cyl over the years. Some times if it's not to bad you can wait a while when it first happens to cool down and limp it home or "on to a trailer" when you buy or sell them! I have never done that to someone. My buddy has a Skidoo right now that we know he seized it up on the lake one day two years ago. He let it cool down started it up and now his wife drives it "unknowingly" because she never goes fast enough to build up the heat to fry it any futher!

[MN Mike]

It's got to be a Fan, no water jacket holes showing.

Thats what I was seeing too but I had to make sure, like I said, I'm not into Polaris' much, some where talking about putting a liquid motor in a fan cool chassis, IMO thats crazy talk, you need the heat exchangers, hoses, coolant tank, different ECU....... lots of work in my book and not cheap!

Mike

[Esox_Magnum]

I'm almost sure all Polaris under 500's are fan cooled, even some 500 and 550's are still fan cooled.