Put it back together and it's worse than before (video)

milo303

milo303

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Joined
Sep 10, 2011
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Location
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Pulled my carbs because I was getting a bog off the line. Since I had someone run my carbs in the fall, I figured I should go ahead and do it and make sure they're right.

Well I'd tracked the bog down to probably being the fuel screws. So I screw them all in from where they were positioned and none were the same....

So I pulled the jets, they were all clean.

Pulled the fuel screws and the opposite cylinder of the pto side was white and cruddy so I cleaned it off. Also sprayed some cleaner in the fuel screw holes and watched the cleaner come out so they're clean.

Put the screws back in and backed them out 2 and 1/8 turns.

Got it all back together and got it started and it's hitting on two cylinders I think. It's also now getting a weird hang up and not wanting to go back down to 1600 rpm all the time.

I'm beginning to wonder if it's jetted right, but mind you I'm doing this work down in Denver and ride around 9-11k feet, but it shouldn't run this choppy all of a sudden I wouldn't think.

I'll keep some more videos coming and feel free to suggest anything for a video that could help with some advice.

It's my first time messing with carbs and I'm scared I'm going to have a melt down.

Oh also I pulled the plugs and pto plug was pretty bone dry while the other two had some oil on them so I opened the oil cable up a little as I'm still dialing in my oil cable since it's aftermarket.

Here's where my videos are

I've got a couple of the choppy sound and some of the throttle hangup. I gotta run into work or I would mess around more.

http://www.youtube.com/user/Milo3o3/feed?feature=context
 
when you pulled your jets did you pull both the low and main jets? every carb has 2 jets in it and the low jets clog very easily. wasnt real specific so just thought id ask.
 
I listened to both videos you posted. In both videos it sounds like you are running on only two cylinders. You should confirm all 3 pipes are getting warm/hot there fore running on all 3 cylinders.
 
looks like your throttle cable is tight..is there slack in the cable??Sounds like a cyl isn't firing..check plugs,wires,caps.And yes did you check your pilot jetss for plugging up and the umbrella type filters at the needle valves.Are the floats in correct spec..maybe needle valve or valves sticking letting no gas in.Take carbs apart again.Drain each float bowl separately and compare how much gas is in each bowl..this will tell you if you aren't or are getting gas in all 3 carbs..but pay major attention to the pilot jets..they are probably blocked creating a lean condition.Everything has to be in harmony in order for them carbs to work efficiently ..also check when carbs are out that the reed petals are in good shape or not..BUT CRITICAL that them carbs are cleaned and adjusted properly...take time on this.do not rush this step...and then report back again

Imagearik0SntIuiZ6hyGermjQElUaribYA.gif


clean #21(pilot jets good)
remove and clean the little umbrella screens #62
and remove clean needle valve assembly #33

of course clean main jets,and spray with carb cleaner thru all openings and passages ,check float levels.Remove your fuel screws and check to see if any of the o-rings and washers are missing on them..be careful as them parts are tiny..CHECK everything out....
 
I'm at work so I can't touch them but I'm reading your replies.

I'll have to see what size jets

The thing is it ran fine before taking it apart except a launch bog which should've been the fuel screw.

I'll rip em out again tonight and do what blue said with the floats and run them again
 
Main jets are 130's

Pilots are 62.5

Both across the board

I've got it torn apart and everything is clean. I did notice the fuel screw on the cylinder in question had some gas on it when I flipped my carbs over. In the pocket that the screws are in
 
it was carb related...seems most guys on here running their sleds for the first time this season have got to get into the carbs first and clean them.To MANY guys having similar issues right off the bat.....CLEAN CARBS..and if the sled stands for weeks after without running..I am afraid you may have to do it again..thanks to ETHANOL in the gas...If the sled is going to stand around a couple of weeks ,you must drain carbs and probably drain the gas tank of that crap also to be safe...pain in the butt or just find Premium fuel without Ethanol.I use only Premium here before no ethanol in it..not taking a chance running lower grade gas..
 
I've been running it every week for the past 5 weeks ( :

Had a mechanic clean the carbs but he didn't do the fuel screws I think. Everything was clean but one of them.

When I went to pull them off again they basically fell out of the Reed cage rubbers so I'm pretty positive that's what it was. Because nothing broke loose and clogged the pilots as they were just as clean as the day before when I ran em.

So I think this one was my fault, I failed to lodge them into the Reed cage boots well enough and cylinder 3 must've been sucking large amounts of air.

Thanks a ton for the posts guys, really appreciate the willingness to help from this forum.
 
Got to ring it out today and the bog is still there even after setting the fuel screws.

It's clean and healthy down in Denver and when I get it to altitude it's wanting to give me a lean bog and during 1/4 to half throttle I would get a bit of a blubber like I was losing a cylinder and then it would pick up if I blipped the gas or if I kept where I was with the throttle.

Really a pain in the arse figuring this out with over 5,000 of elevation and 20-30 degree temp difference

I'm beginning to wonder if my pilot jets jet to go up from 62.5 to 65 to clean up the initial bog or if I should do the reed notch mod and hope that cleans it up.

I took some footage today when it would do it but the sound didn't come thru good enough.

So close to taking my two sleds to the dealer and getting a new one

Anyone else run at high altitudes with bender cans and the airbox opened up who knows what jets they run?
 
If it's good down low and then the bog shows up at higher elevation, then maybe it's too rich on the pilot circuit? The higher the altitude, the less dense the air. Fuel always stays the same, the only thing changing at higher altitude is less air in the mixture...it will get richer the higher you go, leaner the lower you go.
Does blipping the choke help the "lean" bog?
 
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The choke only seems to want to kill it at altitude when it's warm

I've been reading about this low end bog and what I've been seeing is the lean bog is caused by a lean condition and is usually fixed by turning out the fuel screw to fatten it up in the pilot circuit and if you need to go much passed 2 turns, you need to jet up one size.

Am I misunderstanding it?

I've been getting my info here

http://www.hartmaninc.com/tuning.html

And here

http://www.totallyamaha.com/snowmob...g a Sled/Jetting a sled and reading plugs.htm



So if I'm not wrong and I size up one pilot size, and do the reed notch, and it still does the off the line bog, I'm trading it in.

I absolutely cannot stand having issues like this and I'm almost out of options

Not liking the idea of a 4 stroke but I dislike my throttle not being there when I need it even more
 
Someone please inform me if I'm understanding it wrong though....

I don't want to go with larger pilots if I actually need smaller pilots to get rid of the lean bog
 
Have to read the plugs...run it steady between 0-1/4 throttle for a bit, then pull plugs and let us know what color they are.
Since it seems to run better down lower in Denver for you, but then has the bog at higher elevation...plus blipping the choke wants to kill it...then I'm leaning towards it being to fat on the idle circuit, not lean. Hard to diagnose without seeing the plugs, and don't want to steer you wrong...especially when you're so frustrated.
Let me try looking up a jetting chart and I'll get back with you.
 
milo303 said:
Main jets are 130's

Pilots are 62.5

Both across the board
Click to expand...

Okay, here's what was confusing me...
I looked up in the tech pages what the stock jetting is for a 00 MM 700:
It shows the pilot as being a 45...someone please double check that I looked up the right sled, but if a 45 pilot jet is stock, and you have a HUGE 62.5 in there, then no wonder. If I looked it up right, it is terribly RICH on the pilot circuit.
The boys in the Mountain Sleds section could probably help out with jetting specs. Lots of guys in the mtn section running Mountain Max 700's.
 
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milo303 said:
Put it back together

I think I didn't get the rubber surround on cylinder 3 all the way onto the carb, reed box side.

Everything is spotless....

Sounds healthy again and is running on all three. Fuel screws are all at 2 1/8 turns.

http://www.youtube.com/watch?v=-D4WRC5HqWQ&feature=youtu.be
Click to expand...

Are you sure Fuel screw adj should be 2 1/8 turns out? would explain the bog. 130 mains seem too lean with gutted box and can.
 
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