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Discussion Starter #1
Hello SW

I have a 99 MXZ 600 and I rode it yesterday for about 20 minutes on a lake. Then we proceeded to do some ice fishing so I shut the MXZ down and it sat for an hour and a half. When I tried to start it back up it wouldn't turn over. So, the same thing happened a couple weeks ago and that time I put a couple new plugs in and it fired right up. My question is, what would cause my sled to not fire up after driving it for a little while. The plugs that were in the yesterday were new, and only had like 15 miles on it.

BTW, when the sled is cold it will start up on first or second pull! It seems to only have trouble starting once it's been running for a while (warm) and then sits for a bit. Yesterday, I finally did get it started after a little while of trying.

Happy Sledding!

-Michael
 

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When I tried to start it back up it wouldn't turn over.

-Michael[/b]
do you mean it physically would not turn over ? or just not start?
 

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What did the plugs look like ? wet , dry color? . Sounds like a fuel delivery problem or carb adjustment. Have the carbs been cleaned ? . Might be time to replace needle and jets too. If the needle is worn and not seating in the jet it will flood out. Your plugs wil tell the story , wet to much fuel, dry not enough .

mutt
 

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Discussion Starter #5
What did the plugs look like ? wet , dry color? . Sounds like a fuel delivery problem or carb adjustment. Have the carbs been cleaned ? . Might be time to replace needle and jets too. If the needle is worn and not seating in the jet it will flood out. Your plugs wil tell the story , wet to much fuel, dry not enough .

mutt[/b]

The plugs were a little wet.. I had the sled serviced last year and the shop I go to said the carbs looked fine. So, at this point does it look like fuel delivery? Or do the carbs need to cleaned. I have been searching SW for a write-up on cleaning carbs, is there a good write-up on how to do this?

Thanks for all the help! I appreciate it!
 

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The plugs were a little wet.. I had the sled serviced last year and the shop I go to said the carbs looked fine. So, at this point does it look like fuel delivery? Or do the carbs need to cleaned. I have been searching SW for a write-up on cleaning carbs, is there a good write-up on how to do this?

Thanks for all the help! I appreciate it![/b]

Look in the tech section , i think there is one. Your carbs need to be cleaned every fall before the season starts. If your carbs have Any gas in them after cleaning and it sits for some time(over summer) your jets will clog up even if there fogged and sometimes if stabil additive is added.

I clean mine in nov or so after it gets cold .

Next time your out to ride try giving the throttle just a little bit when pulling it over. Just enough to crack the carb slides open, doo's are known for this . It's a fine line of factors air-temp density+ fuel flow to get the fire mixutre to go.

It could be somthing as simple as turning the air screw in (lifting the slid a tic). my 00 mxz did this too. Watch your plug color too , dont want to run it lean (lt brown to white) coco brown - blk dry = good

mutt
 

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Discussion Starter #7
Thanks Mutt.. I saw a tech article on installing reed valves; however, I didn't see a tech article on cleaning carbs. What is the best way to clean carbs? What type of cleaner do you use? The carbs need to be removed in order to clean, correct?

Thanks,
Mike
 

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I am having the EXACT same problem with my '03 mxz 600. fires right up when cold, but not when warm. What 3 different shops have told me is to check the compression. they said that as it gets warmed up and ran for a while it may lose compression. They told me to check it and if it wasn't the right compression, that i'd need new rings. To get you by what i do is have a stick about the diameter of a straw that i wedge in the throttle just to crack it open while i pull and it fires right up. be careful you don't get too big of a stick cuz you don't want your sled to take off!!
 

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To get you by what i do is have a stick about the diameter of a straw that i wedge in the throttle just to crack it open while i pull and it fires right up. be careful you don't get too big of a stick cuz you don't want your sled to take off!![/b]
Better make sure you have your tether cord attached to your suit then and make sure nobody is standing in front of your sled.
Are you not able to slightly open the throttle with your right hand and pull the recoil with your left hand?

Also check to make sure your carb heaters are turned off while it's parked.
In fact most of the time unless you're riding lots of powder in extreme cold temperatures.
Look for the red knob on the hose between your carb and the head. Make sure the knob is pointing straight up.

Jeff
 

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ya my sled does that too, just play with the choke and just keep pullin till it starts..
 

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Discussion Starter #11
I am going to add some stabil and then fillup my tank before I ride on Friday. I will also be cleaning the carbs and checking the main and pilot jets this weekend.

Thanks for the help!
 

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Next time your out to ride try giving the throttle just a little bit when pulling it over. Just enough to crack the carb slides open, doo's are known for this . It's a fine line of factors air-temp density+ fuel flow to get the fire mixutre to go.

mutt[/b]
Mine wont even think about starting warm unless I give it atleast 1/4 throttle
 

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This is a problem on alot of sleds, my 05 is doing it too. From what ive been hearing and finding out.. is the float leaver in the bowls need to be set to close off the main a little sooner. OK here,s what ive been told to do before, when your have your carbs apart, flip it upside down . Look at the brass lever that the float hits to close the jet . You want it to be slightly running up hill rather than straight across. This will close the jet sooner and not alow extra gas in the carb .
When it dose'nt close soon enought it floods and thats why you have to give it some throttle to get it to fire(enough air to have firing mixture). It's a fine line to cure completly ( air temp/density)not to mention all the viberation your carb gets during operation keeps it dancing up and down too. Makuni carbs a simple but are finiky to tune perfect for all conds.


Teamskidoomxz.. you have round slides on yours , those are easy to clean. Just pull your air box , unscrew your throttle slides and hang them off to the side , un do the choke cable just to the left side, un hook your gas lines and then loosen the clamp on you boots and bingo they come right out.
Take the bowls off and all your jets are right there(little one is the piolit , center one is the main).If your bowls are dirty on the bottom inside, then your jets are dirty too. Just be carfull when your disassembling DONT LOOSE ANY THING.

I clean mine out with gumout carb cleaner then wash them with HOT water and blow them out with compressed air.

Flat side are the alittle differant but on the same order. ALSO heated carbs there's just a coolant line in the way.

P.s stabil wont do much for dirty carbs, it just help keep the octane levels up so varnishing dose'nt occur.

Another thing is plug gap, make sure your running 0.18 gap.

mutt
 

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well i ran a compression check on my '03 mxz 600 today and both cylinders were @ 90 lbs which is far from what they should be, so i ordered some new rings and a gasket kit for it. and mine was doing the EXACT same thing as yours so you might wanna check the compression on it. my total cost was $160 with me doin it, which isn't a bad price to pay for trust in your sled while on the trails.
 

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Discussion Starter #16
Porter - I am curious as to how many miles you have on sled? My MXZ currently has 2800 miles.

Mutt - thank you again, I will be using your instructions to clean my carbs. I will post will my results.

Thanks!
 

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my sled also has 2800 miles on it. i think actual is closer to 2750 but close enough. startin tear down on mine in about 2 hours
 

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my sled also has 2800 miles on it. i think actual is closer to 2750 but close enough. startin tear down on mine in about 2 hours[/b]
I think you are wasting time and money. compression is irrelevant unless you know what you are reading. Cheap tester, good tester. Warm or cold. what is it suposed to be... a question normally not even to be able to be answered. I agree 90 does seem way to low, but it may not be your issue.

I have been through a few doo's in my time and like gravey said...
Mine wont even think about starting warm unless I give it atleast 1/4 throttle[/b]
I just hold throttle half and pull and away you go

not saying it isnt the cure but think you are jumping the gun
 

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well i ran a compression check on my '03 mxz 600 today and both cylinders were @ 90 lbs which is far from what they should be, so i ordered some new rings and a gasket kit for it. and mine was doing the EXACT same thing as yours so you might wanna check the compression on it. my total cost was $160 with me doin it, which isn't a bad price to pay for trust in your sled while on the trails.[/b]
Im sure that it might be some of the problem but doubt that it is the whole story on yours. Why is the comprssion so low in the first place? to lose compression w/ low miles there is somthing causing it and it 's normally due to fuel /air mixture. Or it's been rode hard before proper warm up causing cold seizure(piston/rings hotter than jug.

In your case it may be true, but from all the times ive experianced its been in the carb settings. I have a 05 rev ss and it did it from day one, I dont think I bought a new sled with fried rings in it from the showroom . I also had a 00 mxz that did this and I did what I mentioned and it's still running strong with 7 k miles on it with no motor work done to this day.

What were your plugs looking like ? even after your new rings make sure your carbs are up to snuff or your back in the same boat.
I do belive the 02-04 600's did have some issues with rings though , then there's the H.O'S YOU wont get me to buy one .

mutt
 

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well the only reason i got the rings right away is because i have talked to two shops and my friend that used to own his own shop and they all said that rings was my problem. i'm only 16 so i admit i don't know a lot so i try to listen to the shops, and my one friend. they've never steered me wrong before.
 
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