just wondering about running on lakes how long can u run wide open and is it hard on the engine. what should u watch for. my sled is stock.? i,m very scared to run wide open for any longer than 30 seconds.on the lake .can i run longer without any problems. ??? ??? ???

im scared i guess because i blew up my old sled on the lake crank went :cussing: :(

Yes, its hard on the engine. Everything is under full load.

Personally, I couldn't hold my engine wide open for more
than 2500 ft (about 1/2 mile). I've got to blip the throttle
just to make sure I bring down the temps in the engine.

Its the saddest sound when that engine burns down at WOT
on the lake. You know what will happen next. Towed,
tear down engine, order parts, and then rebuild. You know
you'll be down for a week or so. If you are on a trip - you
either sit at the bar and watch your buddies ride or you
shell out big bucks and rent a sled.

You have good reason to be concerned.

ok thanks i will remember that :D :D :thumbsup:

Im scared as well to hold it open any longer then 1 min, but ive brought my 500 through hell and back and it keeps wanting more. I run this sled wide open for 5 min at a time, just killing it. But its still running strong at 10000km.

It all depends on your fuel quality, fuel grade 91 or higher for wide open IMO, and jetting.

Last season my sled saw multiple runs of 2-3 miles wide open. Many times I would do them back to back. It is bone stock and I run 91 octane. Never had any problems.

The way i look at it is like this, a snowmobile motor isn't any different than a chainsaw motor. When i cut wood all day long my saw is wide open from start to finish, i'v never blown my saw from holding it wide open. I'v never blown a motor an any of my sleds while holding it to the bar. They are both two strokes just one is larger scale, besides what about those GP raceing bikes they are also two strokes and they go one hell of alot faster then a sleds do. Also if your sled is still under waranty why are you afraid to hold it open for a few miles on the lake, if it does blow it gets fixed for nothing. We run for miles out on the lake wide open, if your not running on the edge with your jetting then you should be fine. When i pay $7000 dollars for a sled i should be able to flog it, not have to baby it. Most of the guy's that blow there motor's while running wide open are the ones that are modded and running on the edge.

if its stock you can hold it wfo all day long as i have with all my stockers, but.... most of us are rejetted because lean is mean:) now you gotta start worrying about those temps.

paidncash, i disagree a little. surely you dont pin a chainsaw all day long-that would be extremely dangerous. even a saw held wide open during a cut gets a break every few seconds, same thing with gp race bikes-they are on and off the throttle all around the track. personally depending on the sled i might hold it open for a mile or so, but i do tend to think it gets a little stressfull for the motor to stay that way for too long. probably on a stock sled you'll run out of lake (at least where i'm from) before you've held it wide open for too long most of the time.

well i run my wide open for 5 to 6 miles at a time ...with no problem ...i have been doing that since 1971 and have only melted one 440 sno-jet back in 1975 ...i dont do any thing special ,i just dont let of the throttle complitly when slowing down....burp it like a baby and start all over again...

Yes you are right i do shut my saw down to fill it with gas and oil but other than that it's wide open under a heavey load cutting wood. and yes you should be able to run a stock sled wide oped forever without burning down. If you are jetted lean or have other modds then i would be carefull, the thing i fear the most isn't burning down my engine it's blowing a belt that could be real ugly at wot.

Doo test their engines at WOT for 1 1/2 hrs straight, so a minute or two should be OK. Just make sure to have good gas and use stock jetting, it's rich for a reason ;)

One important thing is to run here down step to step from WOT. Running WOT and then drop the gas lever to minimum, will make the engine very very warm at the pistons..U could also blip it down while braking. U have to flow some gas over the engine to keep it cool.

Originally posted by paidncash@Jan 8 2003, 10:07 AM
Yes you are right i do shut my saw down to fill it with gas and oil but other than that it's wide open under a heavey load cutting wood. and yes you should be able to run a stock sled wide oped forever without burning down. If you are jetted lean or have other modds then i would be carefull, the thing i fear the most isn't burning down my engine it's blowing a belt that could be real ugly at wot.
gimme a break under load for the whole day.... how big is the tree you are cutting? When you remove the chainsaw to cut another log, it is not under load still.

Steve

is it hard on the engine then when checking plugs to go from WFO to hitting kill switch?

crazyliver-that was my point too. unless maybe using an alaskan sawmill or something, but even then it would get a break between cuts.

I never hold it wot for more than a mile or so and on extremely cold days even less or not at all.But the 800 doo runs cooler at wot anyways :0:

in mich. up the lake gogibic is 14miles long and our group has been across that full lenghth wfo many times and never took a motor

I had my mxz wide open once for quite some time and started thinking as I was doing this... "This can't be too good for my engine"... and not even 2 seconds after my thought... a huge "Bang!". Scared the heck out of me... expected a grenaded motor. It was just blown belt thankfully... course it broke my belly pan :cussing:

I give the engine some shorter breaks when doing a lake run... on the throttle for a while and then let off a bit for a few seconds and then back on. Seems to work so far.

Its usally the people that baby there engines that are in the shop. Not that there doing anything wrong. Thats just how luck works.

Just like how the lawnmore under the leave in the middle of the feild will fire up first pull in the spring, well the guy that winterized it and stored it has it all apart trying to fix it.

JUST PUT IT TO THE BAR. :D no more then 2miles

GP bikes are designed and setup specifically for the racing condition (each race) and are probably good for about 10 more laps than the length of the race they are in before they blow up. they are right on the edge on purpose and should not be compared to anything that is designed to run a variety of temperatures, conditions, speeds, loads, etc. They are assembled by million $ / year mechanics rather than $100 /day ones. Your sled is as good as the mechanic at the dealer you bought it from (the person who assembles your sled). Oh, yeah and about half of all GP bikes are 4 storkes (with increased displacement to compensate for their lower power/displacement inherent characteristics), and by 2006 2 stroke GP is competely gone.... but i don't need to tell you that do i?

I bet if you charted the RPM of that "all day chainsaw" over time, the resulting graph would look more like the guys blip on a heart monitor.... up-down-halfway up-down... repeat... all day long. Either way... talk about what is real... like the gas to oil ratio of your chainsaw compared to your sled or the rave system implemented on your chainsaw or your weed eater? maybe its a 2 stroke!!! you could tell us about how you keep it wide open for and hour @ 3500RPM!!!!!!!! and its air cooled so it must be hotter!!! (???) ... or compare your sled to sled dogs' food-to-crap ratio. At least you'd be in the same season.

For the first post BIN. That was pretty good. :D

Welcome to the site.



I agree with what you have to say. Mostly with the part about your sled is only as good as the mechanic.

IMO running a sled at WOT for km at a time is not bad for the engine. However it is dangerous for the engine becasue any faults in the set up of the carb/jetting, or quality of gas is going to show up during this time. If your into WOT running, Jet on the rich side, make sure your running a good quality oil, and only use fresh gas that hast been sitting in your sled for that long. And only use 91 plus.

I run a big bore FIII puts out around 190 HP, I run for miles wide open, if it is set up right and you know what you are doing then no problem.

Boy i didn't realize how much of a big deal you guy's would make out of my chainsaw, I'm sorry for getting your blood pressure up. I guess some people like to make a mountain out of a mole hill, but i think you understand the point i was trying to make. Of course i dont hold my saw wide open non stop all day just like i dont hold my sled wide open all day. Come on guy's think about how stupid this is getting, how old are we now. You cant even make a comparison without haveing someone blow it way out of proportion and try to twist it all around. Lets act like adults here and not little babies.

i was just joking paid... don't be offended.

if it makes you feel better i ride a '94 formula Z 583

Hey, I still have my 1998 form z 583...you can't kill it...my dad rides it now... he loves it ...Now I have a rev 600 h.o.x... still like takin the ole 583 out for a ride every now and then...(The Purple Monster) is what we call it...

It used to be that 2 stroke engines were designed for WOT for the expected life of the motor. WE as snowmobilers wanted more power per cubic cc,,, we got it, but sacrificed reliability. Any modifications to a stock setup, only puts more strain upon the moving parts.

Take for example a model airplane engine,, it is designed for 23,000 RPM, and runs on a mixture of nitromethane, and castor oil. It runs non stop at full trottle for it's full life, usually a few years, or 50 hours or so.

Take for example a 493cc Rotax engine,, it can put out 98 horsepower, but for how long? The factory settings are FAT,, that is to say rich,,, more fuel, and oil than you need to have for general conditions. Reguardless of altitude or temperature they seem to go on and on for a lot of miles or Km's. Running FAT is good for longevity,,, but not necessarily best for performance.

It's when we tweak to the lean side that we have problems. This causes burn down. In a 2 stroke, fuel and oil flow account for a lot of cooling.

just my 2c

Troll

Ran my 700 WOT aprox 4 miles across a lake in Quebec last year. Everybody said it would burn down but I had no issues. Motor is moded by MacDizzy and RK Tek. I would not hessitate to hold it WOT for long runs. My WOT EGT's are 1125 so it is plenty safe. It is leaner in the midrange and that is where I'm careful.

ronzx9.