A little off topic...carb question-2stroke sled

[Omega21]

I'm hoping one of the weedwhack...uh...outboard guys can help me out with this. This is the story:
I have a 96 MXZ 583 snowmobile that I've run about 5 times over the last 2 years. In those 5 times, I've had to put 5 sets of plugs in it. The plugs are turning very black, very quickly. It does have the stock oil injection system there...but I'm not real sure I trust it after running the sled for a while. Seems to drink a mountain of gas...and a mountain of oil for the amount of gas it uses. I haven't actually monitored it to see what ratio it's mixing at, but it just doesn't seem right from my experience. The sled is a complete pain in the ass to start when cold, and smokes like a forest fire all of the time. If I pull the plugs out after an "I don't want to start today" experience, they are black, drenched & can be lit on fire with a lighter.
So, with my limited knowledge of 2 strokes, this is my plan so far:
1.Pinch the injection system off & mix the gas to see if it straightens up. This should show if the oil/gas mix is getting too much oil. If it's still wreckin plugs & smokin like mad, then open the injection system back up after I run the gas out of it.
2. Lean the carbs out.
That's the question I have though. How will a 2 stroke tell you that it's beginning to run too lean? I know the plugs will show it, but it seems to me if you get it too lean, it may very well blow up before you get a chance to read the plugs.
Help?
Todd

[Omega21]

Hey I appreciate any info anyone has. And no...I'm not holding anyone accountable. If I blow it up following your advice, then it's my own fault for listening to you.
It's called "Free speech." Say what you like, if I don't like it...then it's MY problem :-)
Todd

[sdba069]

Hey Omega.What he said may somewhat work with a 4 stroke,but not on an engine that burns oil with the gas naturally.I hate oil injection,but your problem sounds more fuelish.Before you disable the oil injection,check with a dealer about the proper oil/gas mix and fill the fuel tank accordingly.Sounds to me like a carb flooding problem,now I assume it's carburated and not injected.You might pull the air box off the carbs and visually check for a flooding condition,i.e. fuel dripping down into the carbs from the boosters at idle.If you don't see a problem there,chances are it may be jetted for a much lower elevation.In that case you will need a factory service manual or check with a dealer for the proper jetting.I've never worked on a snowmobile,but I work on outboards everyday.Hope this helps......Merry Christmas........
Garry

[canuck1]

First of all never trust oil injection on a sled
It sounds really rich and it should start better than it does.
Check the choke see if it is stuck
check the air box for obstructions
check the ignition boxes connections
Is the fuel in it last years
Try a carb cleaner/varnish remover
Run a 40 or 50 to 1 mixture bardol makes good 2 stroke oil
How does this thing run when you do get it to go?

[Jungle Boy]

I have the same sled. They are truely a MFer to start cold or warm. I sometimes have to actually pour gas in the carbs to fire the bitch to life. My sledhead freinds say it's the rotary valves in it that make it hard to start. I think they can be shimmed or replaced. I did have some success by re-jetting it. When I bought it, it had different sizes in each carb. I have also found that if I burn VP fuel or Av-gas it starts better. I feel your pain,,,,,,,when it's time to roll, I get one friend to hold the throttle and one to pull the prick. It's a 2 man operation. They sure work good once it's running th :mad: ough.

[Snowboat]

I've had a few snowmobiles before. Cats and Polaris, even a Polecat. You didn't metntion what altitude you are at. Sounds like it doesn't get run much. I always tore the carbs down every fall because there would be some jellied oil/gas stuck in the small orifices, pilot jets in particular. Putting Stabil in the tank and running it before storage would allow me to skip one teardown and go to every other year. If those were plugged, it wouldn't idle. The sleds that I bought were never jetted for the elevations that I ran at, 6 to 10k feet. They were way off. Weights and springs were too. I'd tear down the carbs, (find someone if this is your first time, its easy after that) lean it out a few notches lower than the dealers altitude recommendation, install new plugs, NGK BR9ES, leave the oiling system alone for now, start it where its warm this first time (if its at the correct elevation), run the piss out of it for five minutes and pull the plugs. If they're wet, black or sooty, jet down 6 or 8, save the old plugs and throw in some more. Don't run to much while dinking with jets, especially this second try, check the plugs after a few minutes. Iwouldn't pour gas in the carbs. WD40 is flammable and has some lubrication qualities. However, a quick snort of starting fluid always worked, but they say not to. Take the airbox out if you're using starting aids. An airbox on fire is not cool. Not very much, they are small engines. I'd fool with the oiling system after all of this. In my experience with sleds and jetskis, its always been carbs, CDI's, jetting, or a mouse nest in the airbox. Good luck, Find a snow bunny to help you, the dealers charge too much.

[beached1]

Are they Diaphram carbs? Mikuni? kehin? I'm not too familliar with snowmobiles but very famil with two strokes. I'm not a fan of Oil injection, but your problem isn't it. You are too fat on fuel. If they are diaphram carbs which I think they most likely are, then your high speed and low speed mixture screws are positioned on the carbs accordingly. Low (and if you have a pilot mixture screw) will be on the bottom and High will the the top. If you have three screws then you have a pilot screw and that will be on the very bottom of the carb, closest to the reed cage. Low will be in the middle. Left to loosen the screw which adds fuel to the mixture or right to lean it out. Obviously, if you screw it all the way in, you've shut that circuit down completely and will sieze the motor.
Put fresh plugs in it after getting it warm and run it at 1/3 throttle for a while. Then take a plug reading. If they are brown, then run it WOT and see if it's your top end that's fat. With a different set of plugs if possible. If you have a pilot screw, then just run it at idle or a "touch" of the throttle once in a while. Make small adjustments accrodingly. I usually go 1/4 tun at a time. Always check the plugs as much as possible while making these changes. Too clean and you're too lean.
Stay away form anyone that might suggest running hotter plugs. Colder is better. Also, if you get the samne "Feel" from two different sttings. The richer of the two is always best.
If this doesn't work or you are not confortable tuning it, then send them (the carbs) to Randy at www.watcon.com (http://www.watcon.com) Randy is the best two stroke engine builder and carb tuner I've ever met.

[Omega21]

Well, I think I've solved the problem. Got it cleaned up, put a new set of plugs in it, fresh gas & some new oil....then called a guy that's been wanting to buy it. Haggled with him a little then watched all my carb troubles being towed away on a trailer! :D
Merry Christmas to me! Merry Christmas to me!
Todd

[Snowboat]

Next time you ask for advice, let us know you don't want it. Give the new owner this advice, maybe he can use it. The problem is not solved by fresh fuel, plugs, and oil. Reminds me of people that tell me, after it blew up, "well I just changed the oil". Did you tell him what was wrong with it when you sold it, or did you just strand him on a remote mountaintop, in Idaho powder?

[Omega21]

Okay, I'll be straight up with everyone here alright? I appreciate the advice, but instead of wasting everyone's time when it became something I didn't have to deal with any longer, I elected to tell everyone what happened with it. I apologize if it came accross like I 'stuck' someone else with the trouble and washed my hands of it. It was more of a failed attempt at a little humor than "look how I screwed this guy."
And just for your information snowboat, the new owner knows full well what's going on & what's been said in this forum. I'm not out to screw anyone on anything, because I've been on the other end of the stick, as I'm sure you have as well.
Also, I may not be a 2 stroke carburetor wizard, but I do know enough to know when things are running alright and when they aren't. That sled isn't gonna strand anyone anywhere. It always went anywhere you wanted, most of the time much quicker than you were expecting. Changing the plugs in the late afternoon was always an irritation, as was trying to start it, but once it was running it was unstoppable.
Sorry if I pissed anyone off. Catch y'all later.
Todd

[Snowboat]

My mistake.

[HOSS]

Direct oil injection can be good depending on the year. Had it on a Yamaha, thoughty it sucked. Most of the VRO units we didn`t set up on the Evinrudes unless customer wanted it. Designed to burn cleaner and save plugs. 80`s and early to mid 90`s it wasn`t up to par. Remember that when you mix your fuel, that ratio is for WOT (wide open throttle).

[DansBlown73Nordic]

I have owned 30+ sleds over the last 20 years. More than likely the oil injection was set very heavy. You could have leaned the pump cable about a 1/8 i.n. with no problems. The reason for the poor starting is the motor is always loaded up with oil.
I run a 97 ZRT800 with a set of D&D ported 900 cylinders,D&D pipes,V-Force reeds....A few other little tricks. The motor makes around 175 h.p.
My oil pump is turned down alot. You can pull the throttle 1/8 plus before the pump arms moves. I put 1500 miles on this motor last year and never skipped a beat....8800rpm's