850 still Bogging and fouling Plugs after Break in

[Mangystone387]

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.

I agree especially with an ecu, there is no way for me the customer to tune it out, so just keep bringing it to the shop, Polaris thinks it’s a fueling issue, I think there is something wrong with that cylinder. If it was a fueling problem wouldn’t it happen to both cylinders, not just pto side?

 

[klarkkentster]

I agree as well. Mine has fouled from day one and now has scuffed a piston - It already had an engine rebuilt prior to me buying at 115 miles - now at 265 miles - and 150 miles of fouling plugs - it happened again. Same failure as before - but different cylinder AND different rider. It's torn apart at the dealer on day three waiting to hear back from Polaris on the plan to repair.

 

[Jaynelson]

What was the determined cause of the scuffed piston (either) time?

 

[klarkkentster]

What was the determined cause of the scuffed piston (either) time?

First time and this time they are yet to definitely pin it on something. Different cylinders and now different riders are making the puzzle more difficult.


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[Mangystone387]

First time and this time they are yet to definitely pin it on something. Different cylinders and now different riders are making the puzzle more difficult.


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I wonder why they decided to tear it down? Low compression or just wouldn’t run at all?

 

[klarkkentster]

I wonder why they decided to tear it down? Low compression or just wouldn’t run at all?

It quit on me new years eve. When I tried restarting it had no power and would pop and backfire

 

[tdelam]

Question

Why is it that people ask the same poor performance questions on just about every snowmobile made before doing the basic troubling shooting first ?

As soon as you have low-end to Mid-range performance problem the first thing that should be done is a cylinder leak down test.

All these problems...... The answer can not be found until you know your motors leak down percentage on each cylinder.

If the cylinder leak down is awesome then the problem is worth discussing.

You should not own a snowmobile unless you have a leak down tester.

You can find them on eBay, or Amazon.

Heck....I will put them on our website if that is easier.

I would absolutely love to see just one person with low end performance post his leak down numbers.

Dan

lol, first time? You mention only one thing and you're so hung up about it. This is totally not going to help a damn thing, performance is fine bottom-mid-top. I remember the first time I learnt my first word too.

 

[pdaddyvr6]

lol, first time? You mention only one thing and you're so hung up about it. This is totally not going to help a damn thing, performance is fine bottom-mid-top. I remember the first time I learnt my first word too.

Why not just do one, it takes all of 10 minutes, and it is pretty much the tell all for the condition of the pistons/cylinders. Even if it passes with flying colors, then you know and all you had to do was pull the plugs....... Just my opinion

 

[Mangystone387]

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

I would like to get in touch with you on proper procedure for the leak down test on the polaris 850, I’m not mechanically challenged, I just want to get the numbers right for sno west and to show my dealer
Thanks
387

 

[klarkkentster]

Update on my scenario:

Recap - I bought used with 115 miles right after first engine was rebuilt. First engine PTO side scuffed piston with no definitive cause of failure. From when I bought it at 115 miles for 7 rides it fouled the PTO side plug every ride. Eight weeks ago took in for updated flash - two rides later on nEw years eve - sled died. Took to dealer - after disassembling motor - Same issue as first engine - scuffed piston - different piston and different rider with agin no definitive root cause. Correction - Polaris authorized Short block and new injectors. Really hope this brings it back to being reliable. I checked on injector part number and it appears it's still the same part number for 20' and 21' model year. With the reported issues with fuel injectors - hoping thats the issue and not farther upstream with ECU or wiring harness. I'm at 265 miles now on the second engine. Hoping to get it back next week and get some more time on it.

 

[Motorbreath_]

This is very disheartening to read.. I've been on two minds about ordering a Polaris this year.. Even considering every Polaris I've owned has given me grief with fouled plugs, or popping pistons. Maybe I should wait out a little bit.

I hope Polaris figures out your sled for you! That's one good thing about them, they do try and try and try to get people's sleds running right.

 

[Teth-Air]

This is very disheartening to read.. I've been on two minds about ordering a Polaris this year.. Even considering every Polaris I've owned has given me grief with fouled plugs, or popping pistons. Maybe I should wait out a little bit.

I hope Polaris figures out your sled for you! That's one good thing about them, they do try and try and try to get people's sleds running right.

My 19 is the best sled I have ever owned. And there have been many. You need to hear some good news too. My 21 is as good so far but too early to report with only about 500 miles on it.

 

[klarkkentster]

My 19 is the best sled I have ever owned. And there have been many. You need to hear some good news too. My 21 is as good so far but too early to report with only about 500 miles on it.

Thats awesome. I really want mine to be solid once I get it back

 

[alldaysammyj]

Thats awesome. I really want mine to be solid once I get it back

Not sure if tis been mentioned yet but perhaps bad oil pump? Or pinched/blocked oil line somewhere?

 

[klarkkentster]

Not sure if tis been mentioned yet but perhaps bad oil pump? Or pinched/blocked oil line somewhere?

They looked at that but figured it would impact both cylinders verses just one each time. Will the new motor come with a new oil pump?

 

[Mangystone387]

They looked at that but figured it would impact both cylinders verses just one each time. Will the new motor come with a new oil pump?

Went for another ride last weekend. It went to the shop, I rode, fouled when I got home, change plugs, ride two days and all good, so far... Idk what’s up with this thing. First time I rode a weekend without taking the hood off so that’s a win, sort of.

 

[klarkkentster]

Went for another ride last weekend. It went to the shop, I rode, fouled when I got home, change plugs, ride two days and all good, so far... Idk what’s up with this thing. First time I rode a weekend without taking the hood off so that’s a win, sort of.

Thats a bummer. My engine gets delivered tomorrow - hope they get it back together this week so I can go test.

 

[Mangystone387]

Thats a bummer. My engine gets delivered tomorrow - hope they get it back together this week so I can go test.

My leak down tester showed up tonight, I’ll get numbers tomorrow.

 

[gopher-it!]

2021 15 hrs broke in on VES EXTREME. 2% leak down @ 100 psi

 

[Motorbreath_]

My 19 is the best sled I have ever owned. And there have been many. You need to hear some good news too. My 21 is as good so far but too early to report with only about 500 miles on it.

I hear sometimes about guys Polaris' actually being reliable, but its few and far between.. When you've experienced the heart ache yourself it really takes a toll on your confidence for a certain brand.

Nothing feels better to ride (especially for my style of riding) than a pro rmk. I just can't do it to myself again though.. and my wife constantly reminds me of the issues I've had with previous Polaris snowmobiles.. lol.

Hopefully someday I can get on another one..