[ReverendHorton]

86 or so Skidoo Tundra. Hasn't been run in the past few years. I put a new plug and some fresh gas and dry gas in... to my amazement it started. Oil is really old so there was some smoke, but I will change that.

My problem is this... there are two tubes coming off the carb I believe that don't connect to anything... at idle fuel starts dumping out of these tubes pretty fast. What might be causing this? We will be taking it apart, but don't really know what to look for that would cause or solve this...

 

[01MXZ800]

YOU DON'T MENTION WHAT KIND OF CARB IT IS,IF IT A MIKUNI CARB CHANCES ARE GOOD THE FLOATS IS STICKING OPEN, TAKE THE CARB OFF AND GIVE IT A GOOD CLEANING. YOU MIGHT WANT TO REPLACE THE NEEDLE AND SEAT WHILE YOU HAVE IT APART.
IF IT IS A TILLOTSON CARB, REPLACE THE DIAPHRAMS AND SHOULD CURE THE PROBLEM.

GOOD LUCK

 

[ReverendHorton]

I think its a mikuni.. don't really know how to tell.
I'm pretty worthless when it comes to small engines. I'll try cleaning it and see where it gets me... thanks for the help.

 

[Fendrguy]

REVEREND,
DONT run it with that dry gas, take it out of there.
The drygas will separate the gas and oil, chances of seizing the motor.

the carb should say the brand right on the side.

Do what MX said it'll solve the prob.

 

[ReverendHorton]

just making sure...
is drygas a threat to all snowmobiles? or just ones that premix? because the sled I'm working with does not need to be premixed. Thanks for the advice.

 

[01MXZ800]

I RUN A HALF A BOTTLE EVERY 3RD TANK FULL AND NEVER HAD A PROBLEM. DON'T USE ONE THE WILL CLEAN THE CARB, I USE THE WALMART SPECIAL

 

[dl_sledding]

REVEREND,
DONT run it with that dry gas, take it out of there.
The drygas will separate the gas and oil, chances of seizing the motor.

From what I understand, if the "drygas" is isopropyl (only, no other dryer), it will not cause a separation of gas and (today's formula) oil. All manufacturers have now formulated their oil to work with isopropyl and ethanol, so it is safe to run in 2 cycle engines. *HOWEVER*, older oil (pre-1996 or so) may or may not be formulated this way. BE VERY CAREFUL mixing this older oil with additives, you may not like the results!

The overflow is probably caused by a stuck-open needle and seat or stuck-down floats, like everyone else has said, which causes the bowl to overfill and the gas to shoot out of the overflow ports. The same thing happened to me on a sled that was run just last year- sat over the summer and shot gas out this fall! It doesn't take much time for this to happen.

I believe that you have a Mikuni carb on that sled, they are very straightforward. You'll probably see some green "gunk" coating everything inside the bowl. Make sure that both the main jet and the idle jet (is that the right terminology?) are clean and and brassy colored when you are done, and you can see light through them. Probably wouldn't hurt to get a carb kit for it, if it's been a long time sitting.

 

[ReverendHorton]

I believe that you have a Mikuni carb on that sled, they are very straightforward. You'll probably see some green "gunk" coating everything inside the bowl. Make sure that both the main jet and the idle jet (is that the right terminology?) are clean and and brassy colored when you are done, and you can see light through them. Probably wouldn't hurt to get a carb kit for it, if it's been a long time sitting. [/B]

you are right... I confirmed last night that it was a mikuni carb. we tried taking off the hose on the air intake side and spraying carb cleaner, but that didnt help much. I'll be taking it all the way off and giving it a good cleaning today, and if that doesn't help, then looks like the carb kit will be needed. Carb kits aren't expensive are they? I really wasn't looking into spending much on getting this back into shape...

speaking of older oil vs. newer oil... is there some trick to draining a sleds oil that I don't know about? I have changed my cars oil many times... but I don't see anything that looks like a drain plug... do I just disconnect the oil line and drain it that way? Thanks again for the help to all.

 

[dl_sledding]

I'll be taking it all the way off and giving it a good cleaning today, and if that doesn't help, then looks like the carb kit will be needed. Carb kits aren't expensive are they? I really wasn't looking into spending much on getting this back into shape...

Just doing a quick search on http://www.denniskirk.com produced Mikuni carb kits for anywhere from $6.00 to $15.00. Very much worth the cost in this case IMHO. You may want to call them first and get the actual part number that you need for your particular sled (you might want to check on the price of floats too) before ordering the part, so that you get the right kit. Or, visit a local sled shop - usually they are more than happy to give some advise to a do-it-yourselfer and potential customer.

speaking of older oil vs. newer oil... is there some trick to draining a sleds oil that I don't know about? I have changed my cars oil many times... but I don't see anything that looks like a drain plug... do I just disconnect the oil line and drain it that way? Thanks again for the help to all.

It's nothing like changing oil in a car. Your car is a 4 cycle engine, where the oil is kept completely out of the combustion chamber and is use just for lubricating the bottom end and valvetrain of the engine.

A two cycle engine mixes the gas and oil together and uses it to lube the bottom end before being forced into the combustion chamber to be burned (look here for a good explanation). Anyway, the point I am trying to make is that you don't "change" the oil in a 2 stroke engine like in your car engine -- it is burned in the combustion cycle and therefore needs to be refilled periodically (VERY IMPORTANT!!!).

You should be able to find a hose on the bottom of the oil reservoir that you can remove and drain the reservoir into a container. Then, you can refill it with new oil. I would recommend a replacement oil directly from a manufacturer, or a *good* brand of aftermarket oil, like Klotz or Amzoil.

 

[busyfixin]

what i have found to work well, is to buy a gallon of carb cleaner, and a few cans of carb cleaner. (should only need one can.) take the carb off, and apart. not just the bowl off, but all the parts too (main jet, pilot jet, needle &seat, floats, basically anything that can be dissasembles easily. put all the parts in a coffee can, and pour carb cleaner over them. fill it up till the parts are completely covered in cleaner. put the lid on the coffee can and let it sit for a few hours or overnight. then take the parts out, and blast them off with the can of carb cleaner. (aeresol) make sure all the brown and green and white deposits are cleaned off, and put it back together. the floats should float in the carb cleaner,so you will have to set the carb body on top of them to keep them submerged. if they dont float, you will need to floats too. a carb kit will include all new seals, and needle&seat, and sometimes a stock replacement main jet. take a look through the main jet, pilot jet,and seat, make sure you can see through them. look at the needle, and make sure there is a little piece of rubber on the end, and that it isnt dryrotted.

 

[ReverendHorton]

thanks again!

just a follow up post to thank you all for your help.
I removed the carb and dissassembled it. Like busyfixin suggested I soaked the parts overnight. The floats weren't too nasty but the little guides they are on were, so I think that was the problem, as many of you have suggested. Either way, I cleaned everything thoroughly.

I just got back inside from putting it back on and firing it up:
No fuel dumping! And it actually idles... something which I can't remember it doing in the past few years without some coaxing of the throttle. Didn't have a chance to ride it around but I think that everything will be fine now.

thanks to everyone for the help. I'm glad I found this forum.

 

[Fendrguy]

GOOD JOB!

Now go put some miles on that bird.

 

[busyfixin]

good work. another old sled saved from the scrapyard.

 

[01MXZ800]

scrap yard? it is a ski-doo scrap yards are not a option, adjust attitude and ride

 

[73Johnson]

Make sure that your needles not sticking open. Clean the Carb and then make sure that the float works properly and the needle seats properly when the float is pushed up,,,,

sorry i didn't read what everyone else wrote