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I haven't turned the valve on to allow the carbs to be heated. I have ridden in -20's F temps. I have had no problems starting when cold. When engine is warm is a different story, I have to apply 1/4 throttle to get the 600 HO to fire on the first pull. 1100+ miles and still running strong.

I never had heated carbs on any other Skidoo. Am I a fool by not running with the heated carbs?

What do you do with the carbs? Heat only in extreme low temps, or not at all?
 

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this is an interesting topic....if you read your owners manual it says to leave them on when its 40 degrees or cooler.......my dealer told me to turn em on at 0 degrees or colder....so i just leave them on.....1300 miles and no problems...
 

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I've never turned them on yet and I've had no problems. Is it harmful if it's cold out and you don't turn them on??????
 

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it's my understanding that the carb heaters are only for clearing ice out of the carbs. This would only happen if you're running in deep powder and the sled was taking in a lot of snow. It would be my natural tendancy to leave them off... colder air means more Oxygen... more hp!!!!

(but then again i've only been riding with carbs for 2 weeks... switched from Cat EFI to a 7c REV, probably won't go back!!!!)
 

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Haven't turned mine OFF yet. I guess because I tend to put faith in the owners manual (silly me). No problems at all with 1800+ on so far...
 

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Hey Guys

I dont have a REV !!!!!YET!!!!!! But I do have a Yamaha with heated carbs. I would imagine that they work very similar. These are the things I have noticed with them

if turned on

1) fuel economy goes to hell (really makes a big difference here)
2) Feels FAT on the low end with ratty sound to exhaust unless around 10deg F or below.
3) I only had icing twice in 5years. Turn on for a couple minutes and icing is totaly gone.
4) If you could regulate the flow somehow, you could actually use this to tune the low end (like with fuel screws only to a lesser degree)

Have you guys noticed the same things?? Do they have this much of an effect on the REV??
 

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Have heated carbs on my REV and my 02' MXZ. Never noticed a difference with them on or off.... they usualy stay where I left them from the previous ride. I try to turn them on in real cold weather (around freezing or below) and off when above that, if I remember of course...
 

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When I first go my son's 02 MXZ 500 trail last year, I followed the owners manual. After bringing in the sled for service and complaining about gas mileage, my dealer said to leave them off unless it's near 0 or below. ,,,,,,,we have'nt turned them on since, even in -0 degree weather.
 

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Im on my second sled with them and have NEVER had them on here in lower Michigan it rarely gets super cold so screw it. Ive never had an icing problem and if I start to there they will be.
 

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I do not use mine unless it is below 0. Do not use them at high altittudes, if you shut the sled off and try to restart in 4-5 min you will flood terrible. Rev 600
 

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I have ridden with them on and off at different temperature, did not notice the
difference. I leave them off when i can ride with gloves and a turn them on when
its cold enough that i have to wear mitten. Sounds funny but it is easy to remember!
 

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For what it is worth, Yamaha owners manual says to leave them on in all temps below 40 degrees F. It does not affect jetting in my experience. Just keeps the outter carb body warm so that ice will not build up.I ran mine "on" all of the time, it's a no brainer when they are on, you need to remember to turn them on, if you toggle back and forth. Forget sometime and you may be bogged down in deep powder, or perhapes a frozen main jet. We all know what that equates to! Just my opinion! But there can be issues of restarting the motor easily after 20-30 minutes on a warm day. I think the carb body stays so warm that it vapor locks the motor and 3-4 pulls are required to restart.
 

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If I did EVERYTHING the manual said to do. I would never have any fun on the Rev.

I was curious as to what others were doing with the heated carbs. I'm having success with them off, so will probably continue to do so.

Am I correct by saying, most if not all Rev 600HO's are having to apply throttle when engine is warmed? Or is that a symptom of bad rings. Or is it because of me running with the heat off the carbs.

Thanks for the feedback.
 

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WHITESTER, you could say most if not all SKIDOOS are aided by cracking the throttle when starting warm. This action doesn't give it more gas, it allows more air into the carbs/combustion chamber to mix with gas. It's not a symptom of bad rings or heated carbs.

If the heated carbs are left on in warm temps (10 or 20 degree and above), the carb bodies get really warm and once you turn the engine off, the fuel in the carb (float bowl) evaporates and you have vapor lock. The longer the engine sits off (up to about 30 mins), the worse it is. In other words, if your heaters are on, you kill the machine and start within a minute, it will probably start OK. It you wait 10 or 15 mins. to start, it won't. Of course, the natural reaction is to think it's flooded, so you crack the throttle and pull away. The carbs are actually out of fuel and turning the choke to full will start it sooner.

In the owners manual, Skidoo still says to turn the carb heaters on at 41 degrees or colder. That's because the greatest chance of carb icing is just above freezing when there is still unfrozen moisture in the air. As air is sucked into the throat of the carb, a vacuum or drop in air pressure occurs which speeds up the velocity of the air and drops the temperature of the air. The unfrozen mosture in the air freezes in the carb and causes frost to build up on the inside and/or outside of the carb.

The second type of carb icing is when riding in powder and snow gets through the filter into the carb. causing A LOT of excess moisture in the carb.

Finally, carb icing can be a problem at really cold temps. (like below 0 F) because the venturi effect inside the throat of the carb drops the air temp way down (like 30MPH windchill effect) causing the body of the carb to be much, much colder than everything else around it. It's not clear to me why exactly this causing frost buildup on the carb, maybe already frozen moisture falls out of suspension and really cold temps (like ice fog at -30 F).

But more importantly, carb icing isn't a big problem for snowmobiles. Why Skidoo added it, who knows? They do tell dealers and customers not to turn them on above 5 F, mainly because it causes more problems than fixes above those temps.

After having vapor lock in my carbs. a few times last year, I've never turned them on and have been fine.

There's a lot of pilots here in Alaska who fly small planes which have had heated carbs on them for decades. The rule of thumb in the flying community is to only use the heaters unless it becomes necessary. That's how I think of our Skidoo heated carbs. They are a tool to use if there is a problem.
 

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I too have to give a little throttle to start when warm. my brother's 02 mxz 800 and 01 XCSP 800 were the same way so I think it is normal. As for the carb heaters, I leave them off till about 0 degrees. I had one instance when they were on at about 34 degrees and we stopped to take a break and it wouldn't start cause it vapor locked the fuel somehow. Least thats what I think happened
. Shut them off, let it sit a while and it started right up.
 

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I ran with mine on for about the first month or so. Had trouble starting when engine was warm so turned off and thought it might help starting but still have to push throttle half way to start. the back fire has gotten better with carb heater off.
 

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I have mine on and i do have to give it some throttel for it to start aswell. is this a warning sign of things to come. i turned my idle up so low idle is around 2000 and you don't need to give it throttle to start. kinda wierd
 

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REV 800X

Regardless of what the user manual says:

I always use them below 15 Degrees F. This method works well.

When they are on above 15 or so, the sled becomes harder to start, when it gets above freezing it is very hard to start. And if you don't have electric start... forget it!

In no case did I ever notice any effect on mileage.
 

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I have had 4 yamahas with the heated crbs and always left them on regardless, the newist one (fathers RX-1 ) doesend even have a shut-off! I have ran my rev 600 with them on and have had no problems starting without applying the throttel. Have trided yamahas brifly with carb heaters off abousoultel no fule millage change.
 
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