Carb Cleaning

M

merc9193

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Oct 3, 2016
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Location
Toledo, OH
Just cleaned the carbs on my 02 viper er's. it was pretty easy my first time cleaning carbs internally. I have 1 question. My fuel screws on 1 sled were 1 3/4 turns (all 3 Screws) in and the other snowmobile they were 2 1/4 turns in. What should they be set at I made the one 1 3/4 and the other one 2 turns for now. They were both bought in Michigan. I will be riding around Gaylord Mi if that makes difference. I just bought them so I don't know how they run for a reference.
 
Merc I've never done my carbs on my 04 but would like to know how. Did you follow the directions in the tech section on this site or just jump in on your own? My 3 carbs are on a rack so I thought the suggested way is to pull the whole rack.
 
steveg,
I would look at the directions in the tech section. Pulling the whole rack out is the best way IMO. Also, I set all the jets in carb cleaner over night. Then blow them out with compressed air. After that, I use a magnifying glass to make sure the jets are clean.

Whenever I go into a carb I haven't been into, I write all the jet and needle numbers down. This way if you do make adjustments, you'll already know what you've got.

Also,

If I'm making changes to the needles, I always refer to a manual to figure out the settings. There's a matrix that helps explain the settings which basically equates to a c-clip, shims, and the needle.
 
Where do you get needles and small parts like that if you need them? Is there a model stamped on the carbs or do you go off the sled model? I'm very handy and mechanical but carbs just make me nervous. So delicate.
 
So I'm going to tackle it. I think I can do it. I'm pretty handy. My normal sled mechanic said he'd gladly consult on the side if I have any questions for free, but I'll drop $50 off for him when I'm done. His time is worth money and if he's helping me, it's worth it. And better than spending $150 to have someone else do it. So I'm confident on the process to clean the bowls, pilot and main jets. I guess the biggest thing I'm concerned about now is just getting the rack out of the sled.

I haven't found any removal instructions on this site or elsewhere. Anyone know of any? I'm talking about removing the airbox (that I can do), unhooking thorttle and choke, any breathers, the fuel and oil lines, etc, etc.
 
Steve,
Go to the home page, look for Tech Center on the left, Snowmobile Tech Center, Engine, and "Carb cleaning 101 with pics by MrViper700". This will help you out quite a bit.

Definitely pull the rack of carbs out and work on a bench.

Here are some basics.

1. Airbox Removal

a. Do not use a magnetic screwdriver. Just get the screws loose then pick up the top cover (remaining flat) which will hold the screws. Do the same for the middle section of the airbox.
b. You will need a long philips head screwdriver to get at the carb boots between the airbox and the carbs.
c. Remove air hose (1) connected to airbox.
d. Remove bolt near steering column that holds air box.

2. Carbs

a. Do not remove the TPS (throttle position sensor) from the carb rack. Instead, just disconnect the TPS electrical connector.
b. TPS stays where it is on the carburetor, otherwise you will need to adjust which requires getting or building a TPS tester.
c. TPS is on the left side in which the connector points upward.
d. Disconnect TORS (throttle over-ride system) electrical connectors. Usually these are two bullet type connectors on the right side.
e. Disconnect throttle and choke connections. Do not disconnect the oil pump cable. This splits off from the throttle cable and routes between the engine side carb boots.
f. Disconnect carb heater hoses. One on each side of the carb bank. Be prepared for a little coolant spillage.
g. Disconnect the fuel lines at the carbs (3). I usually plug each line, however I don't think it matters.


At this point you should be able to wiggle the carbs back toward where the airbox was and out. There's still fuel in the carbs so keep that in mind.

This should help you get them out. I highly recommend taking pictures as you go for your first time.

Also, when you go to put the carbs back in, pay special attention to how the boots seat. A leak can burn up your engine. Also, make sure you do a little research on how to adjust throttle free play, how to set the oil pump cable (very important), and choke free play. Once you get the carbs back in, it's important to set the idle, throttle cable free play, then the oil cable (the one I said to not touch above) in that order. Also make sure your TORS is working. If it's not working, it's usually the result of the throttle free play set incorrectly (not enough freeplay). The engine will also run rough if you give it throttle.

My best advice would be for you to get a service manual and learn how to search this site for info. There's a lot of great info on this site, and good people willing to help you when needed. If you get stuck, just ask.
 
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OldIron, thank you! I have read the carb cleaning 101 stuff, and that did help. Getting everything unhooked seems to be more daunting than the actual bottom end cleaning I need to do. And oh yeah, the fuel filter. I'm guessing that's a large part of why I keep having issues after being so religious about clean and treated premium grade gas. I'll have your directions printed and next to me. Given that I've had the airbox out before, that doesn't worry me, and my mechanic friend gave me some tips on the throttle disconnect and stuff. I have adjusted the oil and TORS in the past too, so comfortable with that.

Honestly, carbs is the 1 thing I have not done on sled. I've done all bearings, chain case overhaul, new tracks, clutches, etc. It's those teeny tiny delicate parts in the carb, and knowing that a screw up could lean you out and lead to a meltdown that has always kept me on the sidelines. But at $150 to get all 3 carbs cleaned each year (and considering I enjoy swinging the wrench on my sleds), it's time to learn...I'm sure I'll be back with questions!

I do have the service manual too and read a ton of threads. Otherwise I don't even think I'd be trying this. :) I find with the service manual though, advice from someone that's been through it can be a huge help as they learn tricks and tips.

Here we go...
 
They are out! That was easy...I'll clean them tonight. Changed the fuel filter too while I had the air box out.
 
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After your first time, you'll want to do it just to know you did it the right way.

Best of luck
 

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just wrapped up cleaning them. 2 of the 3 carbs had junk in the either the pilot main tube or the little holes. One of them had a main jet clogged about 50%. Not gummy green goo from gash though, more just dirt and junk. I replaced the fuel filter as I'm pretty sure the one in the tank may have been original or at least was very old. I would bet it had torn pleats and was letting crap into the fuel system. Everything went back together just fine. A few questions that I'm pretty sure I got right, so nothing to worry about. For example, those little plastic circular things that sit over the main jet tube and fit into the bowl bottoms...I assume they should be fitted loose when reassembling. If you push them down too much they would get stuck behind the pilot jet tube and bind...I was also careful to not overtighten the jets, or the bowl screws. I think I'm in good shape. I just need to put them back in.

Funny though, the holes in the pilot jet are so small, sometimes you think there's something in there, but you realize you just aren't holding it straight up to the light.
 
Just food for thought, BEFORE you re-start your sled, you may wish to pull the motor over a few times with the fuel lines to the carbs disconnected (lay them on some rags) and PURGE out any crap that may be between your new filter and your freshly cleaned carbs. I would hate to pump crap back into "minty fresh" carbs!
 
[emoji23] great idea. Now I need to pull the lines off! Lol. I reinstalled everything already but have not turned sled over or tried to start. Just need to put the air box back in so at least I can easily get to lines and they should slip right off.

A few pulls will cause the fuel pump to pump? I didn't see any wires on it so it's likely not an electric fuel pump so it must.

I'll tell ya that I was paranoid putting it all back together that I didn't get the pilot jets or passages clear enough. Kept cleaning and looking and thinking I was seeing stuff. Lol. Not much to do to blow out the main jet since it goes right into throat. All tiny holes in those jets (over the needles) were clear. But there was no doubt that the pilot passages blew nice and clear. Nice stream of air. [emoji1360]
 
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Northern's idea is a good one. However expect to pull a bunch to move any quantity of fuel.

The fuel pump is a diaphragm type pump. It actually uses air pulses from the crankcase to move the diaphragm back and forth to move fuel to the carbs. These pumps seem to last pretty well but they take a lot of pulling to move fuel when the carbs are dry. Expect a lot of pulling when you try to fire up for the first time after your carb cleaning.

That plastic piece keeps the fuel from sloshing away from the jet during bounces and such. I believe it should be loose like you mentioned.
 
Thanks guys. I pulled it a few times to just clean out the lines from the suction fitting to the carb hookups. Only took about 4-5 pulls. For the actual start I just turned the key. Lol. A tiny bit of choke and she roared to life. Idled perfect around 1600 after a mere second or two of choke. It's 45° here and 55 in garage. And wow smooth! Never been so smooth. And no smoke! Very satisfying. Thank you all for the tips and guidance. I will double check my oil cable slack and TORS Thursday night (busy tomorrow night).

Not sure if this video will post. It let's try. https://vimeo.com/193643271
 
OldIron said:
Nice job. Next time will be a snap. ;)!
Click to expand...

To be honest, I actually felt this time was a snap! Nothing went wrong, couldn't believe it. LOL. But I know what you mean, I bet next time I could do the removal, cleaning and reinstall in about 1.5 hrs total. I kind of spent all day on it this time. Took my time taking them out, then cleaning in phases, then putting back together in phases. Each time something went right I thought "Ok, that was too easy, best to take a break!" LOL.

So a question, are the majority of carb cleanings the lower end in the bowl? The pilot and main jets? On these flat slide carbs, do you really ever have to get into the top unless you need to adjust fuel mixtures and stuff like that?

Now I need to learn how to syn carbs for my other two sleds, whose carbs are not rack mounted.
 
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