2012 Polaris 800 engine burn down, any ideas?

[jrgehrman]

Anyone have any ideas why this may have happened or if it’s going to happen again? Here is the story. I bought a new 2012 Pro RMK 800 last October and took it out to the Big Horns in Late January. The first tank of gas I broke it in as Polaris wanted. I ran 2 pints of oil in the first tank of gas as well as using only None Oxygenated fuel in the sled. The first tank I was nice to it and kept the speed under 50 and the RPMs down. In all I put 170 miles on out west and returned home with no problems, it ran great.

Two weeks ago I made a run to Houghton in the UP. Pulled the sled out of the trailer warmed it up for 5-10 min while I filled the oil and put on my helmet. Still using only none oxygenated fuel in the sled I ran down the trail to the power lines and 6 or 7 miles later my engine burned down.

I took the sled into the shop and they pulled it apart. Inside they found the pistons, jugs and heads all scored, typical lean burn down. When asked why this happened they said they have no idea. My worry is I’m going to get a rebuilt engine with only 175 miles on the sled and it is going to burn down again. Without reason why the first one burned down I’m a little worried it will happen again. It is one thing to be in MI and burn a motor down, but 30 miles out in the mountains is a totally different problem.

Has this been a common problem with the new 11's and 12's?

Any ideas as to what is going on with this engine?

 

[salmonbum]

How fast were you going? How were you holding the throttle? Wer you "feathering" the flipper, or holding it in a consisntant place?

I'm not sure how the RMK's are mapped and how well the FI system calibrates for alititude, but you need less fuel in elevation than on flat land. So if the ECU didn't do its job of fattening up fuel for low elevation, it wouldn't take long for it to burn down. I know a guy that bought a Carbbed CAT set up for mountains a few yrs ago. He thought a quick spin around the yard in Michigan wouldn't hurt. It burned down almost instantly.

 

[whitedust]

It sucks when you don't know why a 2s burned down. I would insist that dealer makes best guess otherwise you will never have confidence in the engine. This why I bought a 4s as 2s & me did not do well. 9000 miles on Yam 4s & nothing but donut replacement in off season never let me down. I feel your pain & hope the repair works. Consider a 4s next time worth the weight to ride out of remote areas. Cats has some nice M 4s to consider. Good luck

 

[raceinsnow]

Have the dealer check the TPS to see if it is set right or if it is defective.

 

[G]

What are the fuel reccomendations for the sled? Are you supposed to be running non-oxy? There is a difference between non oxy and 91 octain and 87 octain.

 

[whitedust]

What are the fuel reccomendations for the sled? Are you supposed to be running non-oxy? There is a difference between non oxy and 91 octain and 87 octain.

Good point & I hear you grub but what the heck these gas stations don't know what they are selling when you inquire. I won't even buy the new Apex Yam 4s because it requires 91 & who knows what you are really getting in the UP boonies. The gas thing with snowmobiles has gone over the top they should design them to run on dog piss & 140 to 150 HP plenty for trail sleds. The subject was an RMK so understand the need for the 2s hp but gas sold at elevation is ususally hot stuff in the UP booines good luck never know what you are getting. There is only 1 premium pump in the town of Phelps & sometimes in winter I have seen the cover off the tank so melting snow can drip in what can a person do? You need gas you do your best & hope for the best. As snowmobilers I think we should let dealers know we don't want premium gas snowmobile engines too much risk to us the riders for an entra 10-15 HP. IMO

 

[Polarice]

Good point & I hear you grub but what the heck these gas stations don't know what they are selling when you inquire. I won't even buy the new Apex Yam 4s because it requires 91 & who knows what you are really getting in the UP boonies. The gas thing with snowmobiles has gone over the top they should design them to run on dog piss & 140 to 150 HP plenty for trail sleds. The subject was an RMK so understand the need for the 2s hp but gas sold at elevation is ususally hot stuff in the UP booines good luck never know what you are getting. There is only 1 premium pump in the town of Phelps & sometimes in winter I have seen the cover off the tank so melting snow can drip in what can a person do? You need gas you do your best & hope for the best. As snowmobilers I think we should let dealers know we don't want premium gas snowmobile engines too much risk to us the riders for an entra 10-15 HP. IMO

Heck when we go out west, not to ride but to camp, I mostly see 87 as about the highest. They have 85 out there which I think is nuts. I may have seen 89, I'm not quite sure....I just know it's low. This is in CO near Loveland and most of the stations in CO that I've seen.

 

[G]

We have had ethanol blends now for a decade plus. It is getting harder and harder to even find non-oxy 92. Even if you can find it who knows how long it has been there and how much water is in it. It is not a fast moving product. That being said I believe all the mfgs now have det sensors of some sort and are supposed to retard the ignition or throw the sled into limp home mode instead of letting it burn down. The new Yamis are supposed to be able to tolerate whatever you put into them. They just don't run as strong if you put 87 in them. In the past Pol used to put switches on the ignition to adjust for ethanol or non-ethanol. The problem here is that folks would turn the switch to wherever the sled runs stronger. Right up until it blows up. Letting the average joe think they are smart enough to fool with the timing on their sleds is not always a good idea. With the gas situation being as it is a person would think that they would all have a foolproof system in place by now.

 

[salmonbum]

Hard to find anything over 91 in Steamboat. Hayden has 93. which is where we fill up.

 

[snoluver1]

Personally, I am extremely doubtful that your dealer would warranty a burn down with no explanation as to what caused it. Maybe if you have a very good relationship with them, they would do it in good faith, but this is a rare exception anymore. My GUESS is they know exactly what caused it, its a known problem, and they're just not telling you.

Pics of the scored piston may help with diagnosis.

 

[whitedust]

Personally, I am extremely doubtful that your dealer would warranty a burn down with no explanation as to what caused it. Maybe if you have a very good relationship with them, they would do it in good faith, but this is a rare exception anymore. My GUESS is they know exactly what caused it, its a known problem, and they're just not telling you.

Pics of the scored piston may help with diagnosis.

Don't agree with that! If Poo dealers will not fix brand new 800 with very low miles why offer a warranty at all? The cause is Poos problem & better figure it out or will happen again at poos cost. Really sucks too have a brand new sled with a rebuilt engine been there done that.

 

[fredster]

Me thinks the lower octane fuel from out west did not work well with the denser air the lower UP elevations. Now if you drained out what you had in the tank from out west and refilled with fuel in the Midwest then scratch this idea off the list.

 

[raceinsnow]

A lean low octane fuel condition will cause detonation and that can be seen on the top of the piston(looks like the piston top was sand blasted with coarse sand).That also can be picked up by the ECM and stored so the tech can see.

 

[900RMtanK]

I burned a piston on my 2010 800 Assault on my first ride back from the Rockies last year. The last pump I was forced to get fuel from was 85 octane. Ran fine that last afternoon out west. Hindsight I should have drained the tank. First ride at home I was going to ride the trail 8mi to fill it up. Never made it. It detected the detonation but not in time. My sled wasn't under warranty but Poo said it should have detected it sooner and retarded the engine to prevent the burn down. They still covered it 100%.

 

[ezra]

Hard to find anything over 91 in Steamboat. Hayden has 93. which is where we fill up.

I bring every can I own and borow a few from buds never know if the party in the lot at night is going to prevent a trip back to town for a few days.kremmling also has 93

 

[Deleted member 10829]

I burned a piston on my 2010 800 Assault on my first ride back from the Rockies last year. The last pump I was forced to get fuel from was 85 octane. Ran fine that last afternoon out west. Hindsight I should have drained the tank. First ride at home I was going to ride the trail 8mi to fill it up. Never made it. It detected the detonation but not in time. My sled wasn't under warranty but Poo said it should have detected it sooner and retarded the engine to prevent the burn down. They still covered it 100%.

Sounds like Poo stepped up on this one! I've had them honor a warranty before when it was out of warranty the prior year. All I had to do was pay a $50 deductible. A year later my buddy had a Ski Doo that was one month out of warranty and the engine went down on a 600, and they said too bad. He had to pay 100% of the bill. The worst part of that story is the first ride in N MN after fixing the engine, he got the sled taken away by the DNR and they told him he could buy it back at their next auction. Ouch!

 

[jeff]

It sucks when you don't know why a 2s burned down. I would insist that dealer makes best guess otherwise you will never have confidence in the engine. This why I bought a 4s as 2s & me did not do well. 9000 miles on Yam 4s & nothing but donut replacement in off season never let me down. I feel your pain & hope the repair works. Consider a 4s next time worth the weight to ride out of remote areas. Cats has some nice M 4s to consider. Good luck

yeah good if you dont like backing up and buying a belt every two hundred miles

 

[ezra]

yeah good if you dont like backing up and buying a belt every two hundred miles

only if you dont get out a socket and tighten 1 bolt on the clutch allinment bar.buy a belt or buy a top end hmm buy a belt or buy a top end decisions decisions

 

[jeff]

REALLY??????????????? where is that in the cat guide. As of last week none of the guys at the cat dealer in mercer knew of anything to fix the prob but to just keep riding and buying belts. JUNK!

 

[ezra]

Really thats funny cuz the recall has been out for well over 2 mo the rags like sno tech have talked about the nut that did not get torqued correct buy the robot so the dealler in mercer is living under a rock or some other explanation lets see what could be the other explanation for the last statment.