1993 Arcitc Cat EXT 580 WILL NOT START - Stumped...

[MontanaKyle]

Here's how it started.

Bought used Snowmobile In Jan, ran fine the first day.

Took out on first outing shortly after that. It took forever to get started once on the trail and ran really rough. Finally got it running but not well. I had added Seafoam per a friend recommendation when I first got it and thought that was causing the rough run possibly. Thought that maybe just ride it for a bit and it would resolve itself

Rode it 20 miles then it just died.

Didn't think to check gas cause there was NO WAY it would have run out of gas, and the gas gauge is broken. Sure enough it ran out of gas, and it was a full tank.

Got it back home added some gas again tried to get it running, noticed gas was leaking from somewhere.

Decided to take out carbs and rebuild.

Lo and Behold one of the Bowl lines was missing the hose drain plug so gas was just draining out the bottom of one of the carbs!

I decided to take them completely apart and clean the snot out of them, added new jets, cleaned them really good, reinstalled with a new Fuel filter and the damn thing won't start.

So we thought maybe just needed a little gas in them to get primed. So we added gas to the carbs and got it running.

Had to remain on full choke in order to stay running. When switched to half or off it would run really rough at half then die when the choke was off.

So obviously it is not getting enough fuel.

Fuel seemed to be going into the filter and the fuel pump but wasn't really coming out of the lines going to the carbs.

So I rebuilt the fuel pump and didn't change a thing.

Checked the vacuum line and the plug that goes into the engine thinking maybe the vacuum is not pulling the fuel through correctly. Well that looks good too.

I am at a loss of what else to look at and try?

Any thought or ideas are appreciated!!!

 

[Mafesto]

Have you cleaned the carbs?


That has to be a EXT Special.
In my opinion, this was the best sled in 1993!
(triple lovers will say xlt special, but they're wrong!)
Throw up some pics when you get a chance!

 

[Sledbrain2]

float out of adjustment, needle out of adjustment,

You have good spark and compression?

 

[rpmboy]

re-clean the carbs they ate still plugged up,pull everything out i.e pilot jet needle/seat ect and use brake clean and compressed air

 

[MontanaKyle]

It's the mountain cat.

Yes I took the carbs apart and soaked them in that engine/carb cleaner for more than 24 hours.

Cleaned everything and put in brand new jets. I do not think they need cleaned, you could have eaten off them they were so clean when I was done.

I reassembled them exactly as I took them apart.

Also as I stated I just rebuilt the fuel pump.

So the fuel pump will get fuel into it but not into the carbs. The vacuum hose is good, the vacuum plug into the engine looks good.

Before it quit running because of a lost plug for the float bowl drain hose it ran fine. It wasn't until after it completely ran out of gas because that stupid plug was missing did I have this problem crop up. I just don't know what else to look at or try?

I'm probably just gonna at leas take the carbs apart again, check everything out and reassemble them but they were clean as a whistle after I took them apart and put new jets in.

I am getting fuel from the tank, into the fuel filter and into the fuel pump just fine. Just doesn't seem to come out of the fuel pump!

The way we got it running after reassembling was adding fuel into the carbs directly, then it would run at full choke, but as soon as we flipped the choke switch to the middle it ran worse, then if you flip the choke switch off it just quit. Like it was getting starved for fuel.

Now it won't start without starter fluid and then will not stay running.

Compression is good, spark is good.

Like I said I've checked all the obvious stuff I'm just at a loss now!

And yes it is a sweet sled. I initially got it for me, then upgraded to a 2006 Skido Rev 800 and using the EXT for my wife. She prefers the older sleds so far.

Here's a few pics. I've already removed one carb after rebuilding the pump and trying to get it to start.

 

[MontanaKyle]

float out of adjustment, needle out of adjustment,

You have good spark and compression?

I just put them back in exactly as they were, would I need to readjust them if it was working before I took it all apart?

 

[Sledbrain2]

I have never took a Mikuni float out, I have adjusted the needle valve buy moving the clip up when going up in elevation, if that were out of spec it would be boggy off the line should not give you any issues starting or idling, If the float is stuck it could restrict gas going in, easy way to check is to remove and see if you can blow air into, should be no restriction. I doubt this the issue, Also can turn carb up side down and see if you can blow air into, should not be able to blow any air into carb, if so then float is letting gas in and flooding. To me it sounds like a fuel pump issue, either the pick up or pump itself.

 

[MontanaKyle]

I have never took a Mikuni float out, I have adjusted the needle valve buy moving the clip up when going up in elevation, if that were out of spec it would be boggy off the line should not give you any issues starting or idling, If the float is stuck it could restrict gas going in, easy way to check is to remove and see if you can blow air into, should be no restriction. I doubt this the issue, Also can turn carb up side down and see if you can blow air into, should not be able to blow any air into carb, if so then float is letting gas in and flooding. To me it sounds like a fuel pump issue, either the pick up or pump itself.

Where would you blow into the carb at?

I rebuilt the fuel pump so it is hard to imagine that being the issue. And when I took it apart it looked good as well.

And where is the pick up?

Thanks I really appreciate it!!! Can;t wait to resolve this.

 

[Sledbrain2]

gas inlet, is where you blow. The pick up are inside of the tank. I had a 93 ext never had an issue with fuel pick up. I did have an issue with the smart valves fuel pick up on an 02 efi, not sure if the carb sleds had smart valves. I believe there is no fuel filter so there has to be a screen on the pick ups. I have no idea how you get into the tank. If you pull the line from tank and get good flow with gravity, if so that is not your issue. Pull fuel line from carb, have someone pull the rope if you get a good stream the pump is not your issue.

Those carbs have a throttle safety mechanism where if the slide freeze up it will kill the spark, might be something to investigate.

 

[MontanaKyle]

gas inlet, is where you blow. The pick up are inside of the tank. I had a 93 ext never had an issue with fuel pick up. I did have an issue with the smart valves fuel pick up on an 02 efi, not sure if the carb sleds had smart valves. I believe there is no fuel filter so there has to be a screen on the pick ups. I have no idea how you get into the tank. If you pull the line from tank and get good flow with gravity, if so that is not your issue. Pull fuel line from carb, have someone pull the rope if you get a good stream the pump is not your issue.

Those carbs have a throttle safety mechanism where if the slide freeze up it will kill the spark, might be something to investigate.

Thanks.

If i take the fuel filter off the line coming from the tank gas flows fine.

If you pull the rope with the line off the carb gas does not come out of the line. Gas is going into the fuel pump, at least the lines are full but doesn't seem to be coming coming out of the fuel pump. But I just replaced all the diaphragms and deals on the fuel pump. Stripped the whole thing apart, cleaned it and replaced everything.

So either

A. The vacuum line is not pulling the fuel hard enough or
B. The fuel pump is not allowing the fuel to flow for some reason?

I'm not sure what else it could be and or how I would test the vacuum line?

Frustrating to no end!!!

Appreciate the guidance and help on this.

 

[MontanaKyle]

EUREKA!!!!

Well I figured it out! So dumb too. Could have saved myself lots of grief and trouble checking easy stuff like hoses thoroughly!

After I took off the fuel filter and attached the hose directly from fuel pump to gas tank outlet pulled it over a few times and still nothing I just started process of elimination.

Siphoned off the gas. Pulled the hose and outlet valve from tank. Noticed the line going into the tank was pretty kinked. Aha this has to be it! Well maybe partly.

So I cut it slightly shorter, reattached everything pulled it over again and nothing! Still no fuel coming out of fuel pump.

I remembered my buddy who is very mechanically inclined said try blowing in the fuel tank and giving it positive pressure to see if the gas flows. Sure enough it did great.

Re attached all hoses to fuel pump and tank, then blew in the tank and covered it with a cloth to keep it pressurized. Sure enough I hear leaking... A hose from the fuel filter to fuel pump had a small hole! I even checked all the hoses but obviously not good enough!

So I am hoping that is it, end of road. Getting new hoses in morning then firing this bad boy up.

At least now I know my fuel pump and carbs are nice and clean. I really hope it fires up now. I'll report back tomorrow.

On a happy note I went sledding today. We got probably a good foot and a half of snow this week up in the mountains. It was EPIC today. Still 8-9 feet up there! Man I love Montana.

 

[MontanaKyle]

Okay I got it running. It really rips! This sled is a ton of fun to ride. It is every bit as fun to ride as my 2006 ski-doo, just different and a different type of challenge.

Turned out my fuel line was also floating in the tank so I replaced that as well.

I am still stumped on one thing though.

I cannot get it to idle correctly.

I set the air/mixture needle to the factory setting, as well as the idle screw. But it will not idle. I've plaved with both screws and it doesn't change it much.

I can get it to start but then I have to constantly be revving it with the throttle and it will stay running then. But will not idle.

Any tips or suggestions on getting it to idle correctly? Thanks!

 

[sno*jet]

check for a bad crank seal maybe.... spray starting fluid around the pto end of the crank where the clutch attaches while its attempting to idle and see what happens.
good luck, i didnt think anyone round here was still messing with old iron

 

[Idcatman3]

Okay I got it running. It really rips! This sled is a ton of fun to ride. It is every bit as fun to ride as my 2006 ski-doo, just different and a different type of challenge.

Turned out my fuel line was also floating in the tank so I replaced that as well.

I am still stumped on one thing though.

I cannot get it to idle correctly.

I set the air/mixture needle to the factory setting, as well as the idle screw. But it will not idle. I've plaved with both screws and it doesn't change it much.

I can get it to start but then I have to constantly be revving it with the throttle and it will stay running then. But will not idle.

Any tips or suggestions on getting it to idle correctly? Thanks!

If you hold the throttle cracked open just slightly, will it idle then?

If so, you just need to adjust the idle up higher. I don't remember exactly how to do that on those carbs, but will find out.

 

[Sledbrain2]

Carbs slides may me out of sync, make sure they move the same and at the same level, I also had a cable come apart right above the slide.

 

[MontanaKyle]

If you hold the throttle cracked open just slightly, will it idle then?

If so, you just need to adjust the idle up higher. I don't remember exactly how to do that on those carbs, but will find out.

Correct they do. And I have messed with the idle screw but it doesn't change it. I'm thinking it might be the float needle. I'm gonna open them up and look.

Also might try synching the carbs. Not sure how to do that but have heard of it.