Sled wont start, HELP!!!

[RedStretchedSled]

almost there

She is almost there, if I just go out, throw it on full choke squeeze the throttle a couple times, do the first initial glug pulls a couple times, then do actual pulls it will start to fire up on the second or third pull, run for about ~10-15 seconds then die. restart the process without the glug pulls, and on about the 5-7 pull it'll run for a few seconds and die. If I give it a little throttle while its running it'll start to "bog"(?) down and kill itself. We will hopefully get to try the compression measuring on it Friday. Is it sounding like a new or more easily understandable/relate-able/fixable problem that any of you have had or know about?

 

[mike_s]

Have you checked to see where the float level is set in the carbs?

 

[karnedge]

set the comperssion..lmao..it sounds to me like your carbs need a good cleaning jets are pluged. has the sled been sitting for a while? years? kids dirtbike wouldnt run at all after a year of sitting and not draing the gas. took the carb apart and it was glazed like a donut. clean and blow out all the ports and holes. fired right up.

 

[sno*jet]

Throughout the day I was tightening the idle screws, trying to compensate for that too (all three at the same time in minimal amounts as well)

"tightening the idle screws" ? if you were screwing them in clockwise, you were raising the idle very significantly. this would require much more fuel though the low speed circuit (pilot jets) to run at the heightened idle you're asking of it, or you'd get a serious lean bog, like your describing. maybe why it ran longer when you covered the carbs with your hands?

 

[sno*jet]

Also, when it ran I adjusted the air idle screws all the way in, and as a base I backed each one about 3 turns out. Started up first pull kept idling (really high mind you,) went to go back them out, started on the mag side 1 turn, center 1 turn, then it died.

"air idle screws" <whats that? you have air screws (small flat blade), and you have idle screws (large spring loaded phillips)
i have not tuned on one of these models before, but 3 turns out on the air screws sounds like way too much. piped ultras run at 1/4-1 turn out for example, if you go too far, it has a serious bog.
"realy high idle" makes me think lean, then you kept un-screwing and she died... i would try them at 3/4 turn out...if we were indead talking air screws here, not idle screws. ?
and if those idle screws are all jacked up now, lower them all down evenly to where they were before. find a drill bit that just barely slides in there under the slide, and make sure all three are set exactly the same height.

 

[WyoUltra]

Right now they're sitting at 1/2 turn out Idle Screws, the spring loaded phillips. And we weren't adjusting them with the filters off the carbs, because it wouldn't do us any good to have that be the only way it would run. We're gonna switch fuel pumps with one off of my sled and see if it makes any difference, also for some reason we can't explain there's the slightest amount of bubbles in the fuel lines, which leads me to think somewhere we're sucking air. If my fuel pump doesn't work we're gonna look at adjusting the float height, and from there replacing the needle & seat.

 

[grampaidso]

Did you ever check the compression?

 

[WyoUltra]

http://www.youtube.com/watch?feature=player_detailpage&v=RYWD6DrnWno
As the description on the video says, sorry for the shaky camera, I was using one hand. My buddy's running the choke with a pair of plyers because the lever broke off about 15 minutes prior to this video. If he keeps the choke engaged it will flood out and die, if we let off the choke it will idle, sometimes surge then die. Part of the video my hand isn't even on the throttle and you can see that the clutches are engaging and the track is running right from the get go. It also seems that if we start it and just run it at 1/3 or more throttle it seems as if it would run all day. The piston skirts look fine, compression is 95 PTO, 92 Center, and 95 MAG. We're also at about 6000'. The only thing we can think of is rebuilding the top end?

 

[WyoUltra]

This is the first time we've worked on the sled for a couple months, kinda got discouraged with it. today we did the Compression test, and we also put some octane booster and an ethanol treatment in it to see if it made any difference. And well it made quite a bit of difference, this is the most constant it has started, usually with 3-4 pulls with the choke. All pipes and heads were warm, so all three are firing.

 

[sno*jet]

at 1:07, somethings up with that throttle block. is that a stock pin going through the lever, or some kind of screw?
there is a safety feature built in that will kill the motor if something fouls up there.

 

[WyoUltra]

I'll have to check, but I don't believe it is. I don't even thing the throttle pushes the pin all the way down into the block I think it stops to rest on it. But I will have to check to be sure.

 

[retiredpop]

"air idle screws" <whats that? you have air screws (small flat blade), and you have idle screws (large spring loaded phillips)
i have not tuned on one of these models before, but 3 turns out on the air screws sounds like way too much. piped ultras run at 1/4-1 turn out for example, if you go too far, it has a serious bog.
"realy high idle" makes me think lean, then you kept un-screwing and she died... i would try them at 3/4 turn out...if we were indead talking air screws here, not idle screws. ?
and if those idle screws are all jacked up now, lower them all down evenly to where they were before. find a drill bit that just barely slides in there under the slide, and make sure all three are set exactly the same height.

Right now they're sitting at 1/2 turn out Idle Screws, the spring loaded phillips. And we weren't adjusting them with the filters off the carbs, because it wouldn't do us any good to have that be the only way it would run. We're gonna switch fuel pumps with one off of my sled and see if it makes any difference, also for some reason we can't explain there's the slightest amount of bubbles in the fuel lines, which leads me to think somewhere we're sucking air. If my fuel pump doesn't work we're gonna look at adjusting the float height, and from there replacing the needle & seat.

Sno*jet is on the right track here. The idle screws are turned way too far in. You need to remove the filters off the carbs and synchronize the carbs. After you have synchronized them you can put the filters back on. You should also do a thorough carb cleaning which means taking the carbs off and removing the float bowl cover. Remove the pilot jet (which has a bunch of small holes in the sides) from each carb and clean it with a very fine wire. The pilot jet is located in a small recess inside the float bowl. It can be removed with a narrow flat bladed screw driver. I wouldn't be surprised if these jets are gummed up and causing your problem. Clean the main jet as well. I am attaching a carb synchronizing procedure for you that does not require the use of a uni-sync gauge.
One other thing while you have the carbs off. You should re-position the needle clip to position #3 as recommended by SLP. #1 will give you a very lean midrange.

 

[WyoUltra]

Sno*jet is on the right track here. The idle screws are turned way too far in. You need to remove the filters off the carbs and synchronize the carbs. After you have synchronized them you can put the filters back on. You should also do a thorough carb cleaning which means taking the carbs off and removing the float bowl cover. Remove the pilot jet (which has a bunch of small holes in the sides) from each carb and clean it with a very fine wire. The pilot jet is located in a small recess inside the float bowl. It can be removed with a narrow flat bladed screw driver. I wouldn't be surprised if these jets are gummed up and causing your problem. Clean the main jet as well. I am attaching a carb synchronizing procedure for you that does not require the use of a uni-sync gauge.
One other thing while you have the carbs off. You should re-position the needle clip to position #3 as recommended by SLP. #1 will give you a very lean midrange.

Ok we'll have to take a look at this, thanks for the carb sync process, much appreciated.

I've never adjusted the air screws myself, however I'm assuming we can tighten them inwards and they'll stop when they're all the way in?

We have cleaned the carbs once, I guess we'll have a second go at it, maybe there's more crud in there. But it will be a while until we can get to it again, we're going out of town this weekend.

 

[WYsteph]

I know my husband has cleaned carbs 2 or 3 times before the sled ran like it should.

What about a bad crankseal?

 

[retiredpop]

I've never adjusted the air screws myself, however I'm assuming we can tighten them inwards and they'll stop when they're all the way in?

Yes they will stop. Just lightly seat them when you turn them in so as not to damage them.

 

[WyoUltra]

I know my husband has cleaned carbs 2 or 3 times before the sled ran like it should.

What about a bad crankseal?

We will check that with some starting fluid, next time we start it up.

Yes they will stop. Just lightly seat them when you turn them in so as not to damage them.

We tightened them the other day and they're about 3/4 turn out, sled popped right off. We're gonna pull the carbs this summer and soak everything in a bucket over night then blow it all out with compressed air. Because it was still really boggy and the fuel lines were sucked clean after about 5 mins. So possibly a clogged main jet and a few other things.