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Discussion Starter · #1 ·
I have a 2009 Polaris 600 IQ, Carbureted. After riding 15 minutes, it slowly idled down and quit. The engine barely turned over - got it started twice but quit a few seconds later then wouldn't turn over at all, behaved just like a really low battery - I could hear the starter trying to turn. I replaced the battery and the problem is still there, and can only get it to bump over a little at a time with electric start, and the recoil start has so much resistance I can't pull it. I removed spark plugs, and drive belt - problem still there, so I suspect a nearly seized engine. 2-stroke oil and coolant nearly full. No idiot lights came on.
Thoughts on this problem? What is my next step? Pulling heads and cylinder casings? or should I first try dumping penetrating oil or auto-trans fluid in the cylinders and let it soak awhile? Could the starter be jamming up the whole thing?
Tearing this far into sleds is new to me, but I have rebuilt car engines and I am an old outboard motor hobbiest, so I'm well-familiar with tearing down those types of engines. I have the factory shop manual.
Thx,
Dave
 

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Does it turn easy from the clutch side? If so, it could be a recoil starter problem. That sometimes happen with snowmobiles with electric start. You should be able to look at the starter to see if it is engaging the ring gear when it's not running to eliminate that as an issue. If there's damage to the cylinder walls, it's unlikely that any fluid in the cylinders will fix it. That's the spendy part.

Good luck, and welcome to the forum!
 

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I would do what Dan says as well then if that checks out then I would pull the carburetors,reeds and exhaust and look into the cylinders before tearing stuff apart and see if there is scuffing on the pistons. If you can't see anything then pull the cylinder head only. You can always buy a new cylinder gasket and o-rings if it checks out. If by some chance you can get it moving again then check compression but that is a big if at this point. Good luck!
 

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Discussion Starter · #4 ·
Thanks for the replies! It does not turn by hand from the clutch side, I'll pull the exhaust and exhaust valves next and take a look - that's faster/easier than pulling the carb. I also have a cylinder borescope but I couldn't see much with it through the spark plug holes - will try that again today and may be able to see more with it through the exhaust. I'm thinkin' it's probably not the starter or it's gear because the motor quit by itself after running fine for about 4 miles.
Dave
 

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Discussion Starter · #5 · (Edited)
Update - 1. The starter gear was not backing off the engine gear-teeth but I was able to move the motor some by grabbing and turning the clutch - I turned it backwards and the starter gear dropped back - still couldn't pull the recoil or get the electric to crank very far - spark plugs out, but with difficulty I could turn the engine completely over by hand with the starter disengaged.

2. I sprayed some liquid wrench lubricating oil in the cylinders and the small tube on the spray can came off and fell in a cylinder - so I had to pull the head anyway. Cylinders looked OK! I sprayed a bit more oil and turned the engine with the clutch and everything freed up nicely! Recoil and electric starter both crank great now with heads off and cylinders oiled. Bearings don't appears to be binding up. No cylinder scarring.

3. QUESTIONS: I have the exhaust valve assemblies hanging off the engine and see that an electric part feeds oil to the cylinders through small holes near the exhaust ports. Is that a small electric oil pump? or an electric solenoid oil valve?. How does that work? I'm not seeing any oil getting through the passages in the exhaust valves as I crank - do the exhaust valve actuators that the pistons push on have to be moving to get oil to flow? or maybe that electric valve or pump or whatever it is died? What turns that electric valve or pump on? I can put 12 volts on that and see if and how it functions, but thought I'd find out how it works through the exhaust valve passage first. Do the bellows in the exhaust valves pulse the oil in?

Update: I found on a circuit diagram, that thing in line with the oil lines is an electric solenoid valve to switch the oil on and off to the cylinders.Opps - scratch that! I found in the manual the solenoid just vents the exhaust valve mechaism to the atmosphere - nothing to do with oil - I thought the line disappearing under everything was oil since it was actuall y rubber gas line stuff - disregard everything I said about it in #3 above.


4. I'm thinking the cylinders quit getting oil and the thing started to seize to the point where the starter would not crank it over. I see in the manual there is a mechanical oil pump buried back by the carb that works on pulses from the crankcase. Maybe that oil pump went bad - is there a way to test it without digging it out??

5. Next thing I'm going to do is put the head back on and check compression to be sure rings aren't damaged or stuck. If compression is OK, I'll get new head-gasket O-rings and re-assemble again.

Bottom line is if I have compression, it looks like the engine is easily salvageable, but I need to be sure the cylinders are getting oil.

Thanks again for helping - I'm learning a lot as I go here!, and the shop manual is vague on a lot of this.
Dave
 

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Discussion Starter · #6 ·
I've been doing more digging and found an oil line to the crankcase at the clutch end leaking where it's connected, and a bit leaked out over summer on the trailer. Now I'm thinking maybe that leak put air in that oil line that went back up to the oil pump and air-locked it, and that caused the pistons to start to cease. I'm going to bleed and test the oil pump per what I learned on a U-Tube. OK - I think I've got it figured out and hopefully still have good rings and compression. Sorry about some of my stupid questions a couple posts up about things I did not yet understand then. Who knew the variable exhaust valve stuff would be described in the electrical section of the manual because of the solenoid? I will let know how things go as I test stuff and reassemble.

I've been digging around the forum and it's a great site! Thank you!
Dave
 

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Discussion Starter · #7 ·
I got the thing started! 130 pounds compression on both!

There is a right angle check valve with oil line connected that goes into the crankcase over the crank bearing that's at the end by the clutch. That is broken - the part the hose connects to looks like a press-fit into the check valve and it has come apart from the rest of the fitting. Part is available so I'll buy one. I'm getting no oil down that line so either the oil pump is bad or it needs bleeding - so next I will dig my way down to the oil pump (removing airbox and carb) and see if I can get it working or if it needs to be replaced. I thought of just running premixed gas, but that bearing may not get lubed properly.
Dave
 

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Hopefully it just needs to be bled. At least you were able to get it going again and check compression. I would definitely take it easy though for the first couple of rides once you get it all fixed before going too fast or crazy on it. Just to make sure it is going to hold up and that the oil pump is working correctly. If anything premix it as well for half a tank along with filling the oil reservoir yeah it maybe a little smokey but at least you know it will have enough oil along with using a piece of tape or something to mark exactly where the oil was when you left say so you know exactly what you started with and how much you used. Also make sure you are using Full Synthetic on that engine as that is what it calls for. Regardless if it has VES Valves or not. AMSOIL is great and has been proven to be better then OEM but if you like OEM, VES Gold is good as well.
 

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Discussion Starter · #9 ·
I'm done and have the sled running great again. Towards the end of my working on it and checking everything, I think I found the main culprit that caused the oil starvation in the first place. The vent in the oil filler cap was totally not working and the cap was on tight. I couldn't blow through the small hole in the top of the cap unless I held the small white plastic dot at bottom center of the cap in and that was spring-loaded to stay shut. Something is loose and rattling inside the cap too - maybe that's normal? I ran a search online for Polaris oil filler cap problems and found a couple of message strings on other forums from the era of my sled that described non-functioning cap vents as being fairly common on Polaris back then. Recommendations were to either replace the cap with vented aftermarket caps, or, drill 4 really small (.020" to .040") holes in the underside of the cap, just through to the hollow part. One repair shop guy said that eliminated oiling problems totally in Polaris sleds in his shop over a several year time span, where before that he had a lot of sleds come back again and again with oil issues. The only problem with the drilled holes is if the sled rolls on its side or upside-down, oil will slowly leak from the vent hole on top of the cap. The malfunctioning parts buried inside the cap are designed to prevent this. Since I'm not in the habit of rolling the sled, I drilled the 4 small holes, and now I can blow air through the cap from the vent hole on top. The oil pump is working fine - to test it, I put the throttle wide open with a rubber band around the handle bar, took out the spark plugs to relieve compression, pushed the kill button down to kill spark, and then cranked the electric starter, and I could see oil entering the carb throats (carb removed to see) and oil coming out one of the crankcase oil lines I had temporarily disconnected. The oil pump itself may have been replaced some time before I got the sled because it didn't have a hex-head bleed screw that the shop manual showed, and no place to put one, either that or eliminating the bleed screw was a mid-year production change. I changed the inline oil filter, and filled it from a pump oil can first and was careful to assemble with oil drooling out so no air got in the line. The old filter was not clogged, but I replaced it anyway. Just to be safe, I mixed a half tank of gas with oil in case I had left any tiny air bubbles anywhere in the lines where I couldn't see them.
Dave
i
 

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That makes sense, if the oil tank goes under a vacuum, that will really decrease the available flow out the pump. The pump only pumps what it can get.

Thanks for posting. Some times it's the little things that matter. In this case, 0.020" ;)
 
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