M7 Deep Powder Running Issues

[307in406]

I ride an '06 carberated M7. When going through deep powder my sled starts acting funny and starts cutting out. When I give it more throttle it doesn't increase in RPM's or speed obviously. It doesn't decrease it just won't increase, like its hitting a wall. If I stop and sit for a couple of minutes or if I feather it, maxing the throttle out, across a meadow it seems to "break" free and run like it should. If I unload off the trailer and ride the trail to where I need to go it hauls and everything is fine, its just when i start going through the powder. I have looked at the boot between the carbs and air box and everything looks tight and good, so I don't think that its sucking snow in anywhere. I do usually mix sea-foam in with my fuel to prevent freezing up. It is running rich also, running down the trail, through the powder, and just sitting there idling it runs rich. I have taken it to a mechanic with the same sled I have and he is running the same jets as well as the same needle and seat positions.

Has anyone ever encountered this problem or have any ideas?

 

[bernard]

I have an EFI M7 that does the same thing in deep snow. I usually just feather the throttle a bit and it picks back up. Been wondering what is causing it though.

 

[bamfm7]

The exhaust is getting plugged by the deep snow. Also if the snow is deep enough the air intake on the sides of the hood will also get resticted by the snow. Speedwerx makes a tunnel dump can to eliminate the powder bog.

 

[sledtahoe]

exhaust smoke

the exhaust is backing up to set off ecu tube.You can seal around can, or i think cat has a gasket to go there now to keep exhaust fo getting in..

 

[Sledbrain2]

I would guess its the exhaust getting plugged. If you got it running right in mixture it will help and should clear it up. If you got a leak in the intake some place that will also cause a bog.

 

[307in406]

I have an EFI M7 that does the same thing in deep snow. I usually just feather the throttle a bit and it picks back up. Been wondering what is causing it though.

Do you have a stock can or aftermarket can? I have heard that the EFI sleds are more finicky and sometimes run better with the stock can.

 

[307in406]

I removed the power valves last night and they were pretty dirty with carbon build up, on the outer edges (left and right). I wonder if a sticky power valve could cause some of this?

I don't quite understand what is meant by "backing up to set off the ecu tube"? I know the exhaust plugging up was in issue with the earlier cat models but I thought that was resolved when they put the exhaust dump out the shock tower?

It seems like its sucking in snow and hitting a wall but I don't know where that would be happening.

 

[Vern]

the ecu tube thing is only for the efi sled the carbed sleds dont have it.

it could be the exhaust plugging, what can are you running? on my carbed m7 i'm running the slp can and i've never had the exhaust plugging problem. the exit of the slp can sticks down about a 1/2"-1" past the stock shield so that might help. i never rode it with the stock can so dont know if it would have been any different.

another issue which i did have to deal with that caused a deep powder bog was the intakes by the headlight getting covered with snow and choking it out. next time it does it lean over and double check they aren't covered. to remedy this this year i took the stock intake screens out and put frogskins in place of them, they don't seem to collect snow as bad. also i took the intake plenum out that runs under the headlights and installed some flowrights in the top of it then installed some of them vents in the dash next to the speedo. so far this year i've had no more bogging issues.

also on the jetting issue, i dont know what elevation you ride at or what jetting you have but if its stock there is definately room for leaning it out. i have a speedwerx pipe and a modified stock head from RKT and i'm currently running 1 size leaner main than what the sticker says for my elevation for stock. and i could probably drop the pilot a size or two as my sled tends to load up when it idles.

 

[jasn179]

the ecu tube thing is only for the efi sled the carbed sleds dont have it.

it could be the exhaust plugging, what can are you running? on my carbed m7 i'm running the slp can and i've never had the exhaust plugging problem. the exit of the slp can sticks down about a 1/2"-1" past the stock shield so that might help. i never rode it with the stock can so dont know if it would have been any different.

another issue which i did have to deal with that caused a deep powder bog was the intakes by the headlight getting covered with snow and choking it out. next time it does it lean over and double check they aren't covered. to remedy this this year i took the stock intake screens out and put frogskins in place of them, they don't seem to collect snow as bad. also i took the intake plenum out that runs under the headlights and installed some flowrights in the top of it then installed some of them vents in the dash next to the speedo. so far this year i've had no more bogging issues.

also on the jetting issue, i dont know what elevation you ride at or what jetting you have but if its stock there is definately room for leaning it out. i have a speedwerx pipe and a modified stock head from RKT and i'm currently running 1 size leaner main than what the sticker says for my elevation for stock. and i could probably drop the pilot a size or two as my sled tends to load up when it idles.

he hit it right on the head them damn triangle vents plug off keep them clear keep it running i have snow stick to em on a sidehill bog down and reach down clean em off game on

 

[307in406]

the ecu tube thing is only for the efi sled the carbed sleds dont have it.

it could be the exhaust plugging, what can are you running? on my carbed m7 i'm running the slp can and i've never had the exhaust plugging problem. the exit of the slp can sticks down about a 1/2"-1" past the stock shield so that might help. i never rode it with the stock can so dont know if it would have been any different.

another issue which i did have to deal with that caused a deep powder bog was the intakes by the headlight getting covered with snow and choking it out. next time it does it lean over and double check they aren't covered. to remedy this this year i took the stock intake screens out and put frogskins in place of them, they don't seem to collect snow as bad. also i took the intake plenum out that runs under the headlights and installed some flowrights in the top of it then installed some of them vents in the dash next to the speedo. so far this year i've had no more bogging issues.

also on the jetting issue, i dont know what elevation you ride at or what jetting you have but if its stock there is definately room for leaning it out. i have a speedwerx pipe and a modified stock head from RKT and i'm currently running 1 size leaner main than what the sticker says for my elevation for stock. and i could probably drop the pilot a size or two as my sled tends to load up when it idles.

I am not exactly sure what can I am running. I bought the sled last year, I do know its not the stock can I just don't know what brand it is. I will have to look and see.

I don't think my side vents are causing the problem because it does it going across meadows also. Until that is I feather the throttle enough, depressing it all the way, that it finally breaks free/clears up or whatever it does and then it runs good.

I usually ride in elevations around 9,000 - 10,000 approximately . My main jets are 320's I believe. When I'm running down the trail, boondocking, or just idling it smells like its running rich. I do think I need to lean it out a bit because of this and the spark plugs aren't brown like they should be. If I am going to lean it out just a little do I need to change my mains?

 

[furthur]

Reading this post with interest...my stock M7 EFI has always run good, no can, but has just started doing this. I just went through it and changed plugs, cleaned valves and adjusted, checked clutch springs, reset deflection, checked fuel, checked for ice in air intake...nothing seemed like it should cause this, yet when I loaded it back on the trailer, I could feel it burbling...like it's loading up...plugs looked very rich, in spite of running an adjustable fuel pressure regulator, at what used to be 42 psi (guess I need to check that again, but they don't usually move...?).

Anyway, keep throwing ideas out.

 

[Vern]

I am not exactly sure what can I am running. I bought the sled last year, I do know its not the stock can I just don't know what brand it is. I will have to look and see.

I don't think my side vents are causing the problem because it does it going across meadows also. Until that is I feather the throttle enough, depressing it all the way, that it finally breaks free/clears up or whatever it does and then it runs good.

I usually ride in elevations around 9,000 - 10,000 approximately . My main jets are 320's I believe. When I'm running down the trail, boondocking, or just idling it smells like its running rich. I do think I need to lean it out a bit because of this and the spark plugs aren't brown like they should be. If I am going to lean it out just a little do I need to change my mains?

if its rich it could be loading up a bit and then finally cleaning out when you feather it, just another thought. on the jetting i know i ran 320s down to 6000ft with just the recut head before i put the pipe on so i would think you could go a bit leaner at your higher elevation. as far as wondering what jet to change it depends on what throttle position you want to lean out. as a general rule pilot jet controls from idle to about 1/4 throttle, needle controls from about 1/4-3/4 and main from there to wide open but they all slightly effect each other. i believe the proper sequence is jet the pilot first, then the main, then the needle last.

further- just another idea but you might already do this. when my brother bought his efi m7 the guy he bought it from told him every once in a while run some injector cleaner through it or else it would do this same thing start to cut out a bit or get a little boggy so my brother has been doin this and so far he's had no issues with it. did you check the little tube coming out of the brain box to see if its plugged or got water in it i hear they are pretty fussy over that little hose.

 

[307in406]

if its rich it could be loading up a bit and then finally cleaning out when you feather it, just another thought. on the jetting i know i ran 320s down to 6000ft with just the recut head before i put the pipe on so i would think you could go a bit leaner at your higher elevation. as far as wondering what jet to change it depends on what throttle position you want to lean out. as a general rule pilot jet controls from idle to about 1/4 throttle, needle controls from about 1/4-3/4 and main from there to wide open but they all slightly effect each other. i believe the proper sequence is jet the pilot first, then the main, then the needle last.

further- just another idea but you might already do this. when my brother bought his efi m7 the guy he bought it from told him every once in a while run some injector cleaner through it or else it would do this same thing start to cut out a bit or get a little boggy so my brother has been doin this and so far he's had no issues with it. did you check the little tube coming out of the brain box to see if its plugged or got water in it i hear they are pretty fussy over that little hose.

What little hose would that be? Do the carbed sleds have that little hose? I have been looking for a service manual for my sled online but I have been unsuccessful.

I will look into the pilot jet first and see what that does. I really need that service manual though so I have more information about how to do this stuff.

 

[Vern]

the hose is just on the efi sleds, that part of the response was more geared towards the other guys questions on the efi sleds.

 

[307in406]

Does anyone know where I can get the full service manual online? Even a download would work.