Engine bog/stall out in low gear under load

[Steamboat Viking]

I just bought an '11 VK Pro and am using it for backcountry skiing. It is the perfect machine for it! However, riding up a steep grade yesterday in low gear, it bogged down then the engine cut out. Riding in low gear with 3 guys on it. We had to turn the sled downhill and choke it to get it going again. Happened a second time, at which point we switched the carburator heater off and switched gears from low to drive. Seemed to be problem solved. I guess I have 2 questions--when is low vs. drive gear called for? And is it possible that switching off the carb heater would solve an issue like this? Thanks!

 

[MrSled]

Carb heater would have not made a difference but it could have been the angle with the load that caused it to die. Maybe the floats are not set right and it was starving for fuel.

 

[BACK COUNTRY YAMAHA]

Low range is good for speeds up to 80kms what caused your bog is when the sled gets really hot with the carb heat on, it vaporizes the fuel thus starving the engine causing bogging or stalling . Had it before on my 06 pro, worked my sled hard in warmer temps and forgot to turn off the carb heat ( which is the same coolant from the engine ). when using low range the sled is pulling higher rpm depending on the speed that you are travelling at. check your owners manual, it tells the temp in which you should turn off the carb heat! cheers !

 

[Steamboat Viking]

Carb heater would have not made a difference but it could have been the angle with the load that caused it to die. Maybe the floats are not set right and it was starving for fuel.

Thanks for the input. I'll check the floats...but the thing is, it worked fine in D after that...so maybe not the floats?

 

[Steamboat Viking]

Low range is good for speeds up to 80kms what caused your bog is when the sled gets really hot with the carb heat on, it vaporizes the fuel thus starving the engine causing bogging or stalling . Had it before on my 06 pro, worked my sled hard in warmer temps and forgot to turn off the carb heat ( which is the same coolant from the engine ). when using low range the sled is pulling higher rpm depending on the speed that you are travelling at. check your owners manual, it tells the temp in which you should turn off the carb heat! cheers !

The sled was probably getting pretty hot--it was a 25* hill, and it was really warm out--like at or above freezing. Would you recommend L for climbing a hill like this, or is D fine, do you think? I was thinking L was for extra power...Thank you for your feedback!

 

[YukonMP]

When Yamaha says low is good up to 50 mph I take them at their word. If I have any kind of load on or am climbing low is good for me. Think about this,, all things being equal the clutches are going to compensate for the difference any way but if you need some jam you are already in low. My bet is one carb heaters too.

When I get stuck are your two buddies available.

 

[Steamboat Viking]

When Yamaha says low is good up to 50 mph I take them at their word. If I have any kind of load on or am climbing low is good for me. Think about this,, all things being equal the clutches are going to compensate for the difference any way but if you need some jam you are already in low. My bet is one carb heaters too.

When I get stuck are your two buddies available.

I'd love to send them up to you! They were great--did all the lifting! Thanks for your input.

 

[Steamboat Viking]

I'm baaacckk! Took the sled out today. Dogged out on a gentle uphill and died. When we tried to increase throttle, it died. Couldn't start it till we spun it around and pointed it down a steeper pitch. Warm day--carb heater off. Full of new, 91 octane, ethanol-free gas.

To start it, we had to have the choke full on, but couldn't use the throttle till we turned off the choke. Starting was like a modified jump start...we were facing downhill and as I turned the key, the gears engaged and it started to move forward, then caught. Wouldn't come close on flat ground...Then, after getting it going again, it seemed to run fine. I'm guessing there's either a fuel pump or fuel filter issue...any guesses? Thanks!

I think it's going to the shop, but want to have some idea of what I'm talking about when I get there

 

[maim]

replace the fuel filters and try it again.

 

[Steamboat Viking]

Thanks for your input I'll do that. Funny thing though: I rode yesterday for an hour with NO problems. The stall out problem only seems to happen under load and uphill. And not all the time. Ran a can of Sea Foam through the engine to see if that would make a difference. I'm using 91 octane non-ethanol gas, so there shouldn't be any residue in the carbs...