go to your dealer and have a compression test. if you blow plugs, your compression too low and 99% your cylinder\ piston are started to go down(ripped). your pto crank bearing moved slightly toward the connecting rod balancer depriving that cylinder from requiered lubrification. we have several sleds that went down with this problem.
850 still Bogging and fouling Plugs after Break in
- Thread starter MDEVO
- Start date
Compression checks are very poor tests..... Let say 1 guy gets 125 pounds in 1 hard pull.
The next guy gets 125 psi but it takes 3 hard pulls to get there.
Same results...... Completely different means to get to the number.
Compression tests are not a good test.
One of my posts talks about low to mid performance problems......max RPM problems are really the first sign of a top end losing ring seal.
So...... For the most part any performance problem where you feel performance is sub-par anywhere from low thru wide open you should do a leak down test.
These test are done with compressed air..... And a % of ring leak is measured.
You will have to hold the clutch with some type of device of your choosing to hold the crank from spinning.
This summer we plan on starting a new in shop YouTube weekly video series to show many shop procedures we preform that Polaris dealers have not been taught in the Polaris service schools.
Dan
Dan
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Leak down test
Before anyone does a reflash, you should first do a cylinder leak down test.
Motor Performance before the reflash...... And performance results after reflash are worthless without leak down numbers.
The big problem with reflashes is...... ( we do NOT know the leak down % on the sled Polaris is using for the mapping ).
Are they using a brand new motor ? With 3-1/2% leak down?
Are they using a 500 mile motor ? With 1-1/2% leak down that had a great cylinder finish and rings sealed up nice ?
Are they using a 500 mile motor ? With 7% leak down that has rings that are on their way out the door...... ( basicly junk )
You see if we knew everyone's numbers...... Then we could see who's sleds the reflash works on and if there is a correlation to the leak down numbers.
And there will be........
If you build a map on a sub-par motor the map is basicly worthless to everyone except another guy with the same sub-par motor with the exact same leak down.
If you build a map on a broke in motor with 1-1/2% leak down...... The Map will be awesome for everyone with a good solid top-end with good % numbers.
As I have said...... All the different results are worthless to the masses without leak down numbers
Dan
Before anyone does a reflash, you should first do a cylinder leak down test.
Motor Performance before the reflash...... And performance results after reflash are worthless without leak down numbers.
The big problem with reflashes is...... ( we do NOT know the leak down % on the sled Polaris is using for the mapping ).
Are they using a brand new motor ? With 3-1/2% leak down?
Are they using a 500 mile motor ? With 1-1/2% leak down that had a great cylinder finish and rings sealed up nice ?
Are they using a 500 mile motor ? With 7% leak down that has rings that are on their way out the door...... ( basicly junk )
You see if we knew everyone's numbers...... Then we could see who's sleds the reflash works on and if there is a correlation to the leak down numbers.
And there will be........
If you build a map on a sub-par motor the map is basicly worthless to everyone except another guy with the same sub-par motor with the exact same leak down.
If you build a map on a broke in motor with 1-1/2% leak down...... The Map will be awesome for everyone with a good solid top-end with good % numbers.
As I have said...... All the different results are worthless to the masses without leak down numbers
Dan
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Polaris fix
I have been brand loyal to Polaris for a long time and it bugs me reading all these posts of guys trying to figure out the problem to why there NEW 850 runs crappie. I snow checked and new 850 163 this year and I must say it’s been pure disappointment from the start engine bog from day one. The sled is bone stock it now as almost 30 hrs and 400 hundred miles still no change. I have spent a tone of money on clutch setups, spark plug gaps, compression test, leak down tests, the sled as been reflashed. Everything checks out, there or no codes being thrown. It’s march now and sled is still in the shop. I’m coming to the conclusion that Polaris doesn’t know how to fix it. ITS MARCH. We all bought these sleds good faith and Polaris is not resolveing this problem in good faith. I think we should ask for r money back. With all that said I have found a fix’s to this engine bog problem. I bought a new 2019 summit 850 sp 175 and all my problems went away. I never thought buying a new ski-doo would b the fix but the best part there’s no engine bog, it starts, it’s fun to ride. I feel bad for all you guys with this engine bog it sucks. Thought I would share how I fixed the problem good luck to all of you
I have been brand loyal to Polaris for a long time and it bugs me reading all these posts of guys trying to figure out the problem to why there NEW 850 runs crappie. I snow checked and new 850 163 this year and I must say it’s been pure disappointment from the start engine bog from day one. The sled is bone stock it now as almost 30 hrs and 400 hundred miles still no change. I have spent a tone of money on clutch setups, spark plug gaps, compression test, leak down tests, the sled as been reflashed. Everything checks out, there or no codes being thrown. It’s march now and sled is still in the shop. I’m coming to the conclusion that Polaris doesn’t know how to fix it. ITS MARCH. We all bought these sleds good faith and Polaris is not resolveing this problem in good faith. I think we should ask for r money back. With all that said I have found a fix’s to this engine bog problem. I bought a new 2019 summit 850 sp 175 and all my problems went away. I never thought buying a new ski-doo would b the fix but the best part there’s no engine bog, it starts, it’s fun to ride. I feel bad for all you guys with this engine bog it sucks. Thought I would share how I fixed the problem good luck to all of you
Team gold/black with radial roller bearing and 2 hardened steel plates under the spring cup. 5000-8000 ft.
Wow!
My buddy fixed his 850 problem as well.
He went out and bought a 2019 800 RMK and has been happy ever since!
Easy if you have the means.....but no an option for most of us....
I am curious to see which sled he will ride once the 850 gets rebuilt?.
I am having that same issue 400 miles and 20 pto side spark plugs. I also leave a wicked exhaust trail in the snow. The plugs only seem to foul when loading or unloading the sled
I’ve done a fuel pump, 2021 re-flash, injectors, wiring harness, exhaust valve relearn and tested oil pump pressures, always the same result
K
klarkkentster
Well-known member
Mine did the same thing. Fouled every ride - now it’s at the dealer possibly getting it’s second motor in 265 miles. First engine went at 115 miles. (Before I bought it) If it fowls when I get it back with the same consistency I will look at the same option you went with.
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K
klarkkentster
Well-known member
Mine as well. Unload - ride for a few to confirm it’s running in one plug - replace plug- ride all day - load on trailer - repeat.
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That is my program exactly, mine is at the dealer now as well, see what they come up with. Have you tried running VES gold or one size hotter spark plug
K
klarkkentster
Well-known member
I haven’t tried a hotter plug in fear of warranty coverage. I have been running the VES extreme since new. Excited to hear what info you get back from your dealer. Wondering if all of us should ping Polaris as well. I need this sled to be reliable. Getting towed from 10 miles back in the backcountry was no fun.
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We’re you leaving the exhaust trail in the snow like I described, at the truck runs ok then out on the mountain that thing is like a coal train, you can see my trail anywhere on the mountain, what happened when it blew up
K
klarkkentster
Well-known member
Mine wasn’t that bad. Once warmed up there wasn’t a bunch of excessive exhaust trail
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On my 19 with the 2020 flash I was running 3 heat ranges, (6's) hotter and Iridium tips. It ran way better on the bottom where in and out of the throttle playing in the trees seemed to load it up a bit. I went back to 9's with the 2020.5 flash but will likely end on 7's.
I got another fuel pump installed, the last one was over pressurizing. I ran it 35 miles. Flawless, good power, hitting my rpm, no smoke trail. I went home it sat on the deck for 2 hrs went back to unload it and fouled another pto plug. #21 on the plug count.
Did it have any codes with he high fuel pressure?
No, the computer has never thrown a code,
I find it hard to believe that fouling plugs is even a thing any more. I rode with a bunch of new or newer Polarises this week, and they all seemed to struggle with runability issues. I’m definitely not anti-Polaris, but some of those issues are stuff I don’t think you should have to be concerned with on modern sleds.
