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Discussion Starter #1
Hello,

I'm new around here...looks like a great forum.

I own a 1996 ZRT 800. A great sled when it starts.
Actually I would never trade it!

Lately it has been acting funny. On a cold start attempt (usually in the morning) it always seems to foul the plugs.

My friend thought it may be running to rich and adjusted the carbs and choke to a leaner setting last weekend and the sled ran great. Today was the first time since the weekend that I tried to start the sled, and the same old problem is occuring again. We though we had it cured with the carb adjustments.

Could it be something electrical causing this to happen? We have adjusted everything on the carbs that can be adjusted (air screws/idle screws/choke cables/trottle cables etc. etc.) so I am beginning to rule out carburator adjustment as the problem.

Anybody have any idea or experience this problem before?

If I install a fresh set of spark plugs in the sled, it will fire right up and work fine all day. Just cold starts I am having the problem.

Also like to add that when it do fire up (not very often) it will idle very rough and at a very low rpm (almost 0) and then backfire and die.

Now when I actually get moving (when it starts and actually will idle) I can drive it for a while and when I stop, the idle will hang at 1200-1500 and then start to die S L O W L Y !!!

Then I am back to the near zero idle speed again. Give it a little trottle and it gets smooth and sounds o.k. Let off trottle, and it quickly dies to near zero again!

I am very fustrated. Any help would be appreciated. I read a couple of post which mentioned replacing the seat and needles in the carbs.

Thanks for any help.
 

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Any chance this started after you put a new belt on. Some times if the belt is draging on the clutch you get similar symtoms. I hear you adjusted everthing but I still think the answer lies in the carbs and the idle and idle air circuts in particular.
 

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Probly not electrical...you said "seems to foul" on start. What do the plugs look like when that happens? Did the sled sit for awhile with gas in the tank and carbs? My Mach 1 did this to me but I have a primer. So whenever it would start to go sub-idle I would give it a prime and it'd crank right back up to idle, for 10 sec. I tore apart the carbs and found NASTY goo throughout the carbs. I thought I'd need to replace the low-side jets, but they seemed OK after I cleaned out the crud. Not sure if this is the case on yours as you have a choke, but if your sled sat around awhile it's possible.
 

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The slowly dying after riding a while tells me that your carbs aren't adjusted correctly for idle. We need to find out if the problem is too much or not enough air. Next time the sled starts to die out after riding, give your choke a quick shot (on then off again, quickly). Does the idle pick up and get better for a few seconds or does it die out faster???

If it's better with the shot of choke you have a "too lean" situation at idle (too much air and/or not enough gas). This can be your carb adjustments and/or partially plugged pilot jets in the carbs.

If it's worse with a shot of choke then you're dealing with a "too rich" situation, which should iron out with spot-on carb adjustments.
 

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if it is flooded in the morning, it could be the needle seat is not working and letting the engine fill with gas overnight. once you start it for the day and it is good to go thats what i would look at.
 

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My buddy had the exact same problem with his 1995 ZRT 800 when he first got it, he took the magnites off the carbs (a safety incase ice build up in carbs) they shut the sled down if the carbs stick, but they don't work well, and they are more trouble than they are worth, he took them off, and it was fine, I am also thinking of taking mine off this summer.
 

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Discussion Starter #7
Hello again and thanks for the replys.
I had already bypassed the safety switches last year on the sled. I had a problem with those as well (bogging when driving around slow).
I am starting to lean towards the needle/seat problem in the carbs. I am going to let it sit overnight with the fuel line shut off. This should keep the fuel from entering the engine.
I will post my results tomorrow.
Thanks again for the replys.
 

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This really sounds like my Ultra. I changed the needle n seats and the engine still fills up with gas. I have another thread asking for help, and the guy's came up with my fuel pump needing a rebuild. I'll be doing that soon.
 

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My sled would do kinda what your saying it would foul up plugs when putting aroud or idling it was good if you clould get the rpms up. I went throught a lot of plugs finally i found something that worked i put new sparkplug ends on it made the airbreather easier for air to get in and i also downsized the jets from 280s to 270s and the sled works mint now oh i also got rid of the choke and put a primer on it choke was starting to stick on the odd time.
 

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Discussion Starter #10
I shut off the fuel last night after a run and let it sit overnight. It did the same thing again this morning...no go. I put a fresh/warm set of plugs in and it fired up with about 1/2 a pull with no choke.
I'm starting to lean towards something electrical. Could it be a weak coil(s)?
 

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Big800 if you know which cylinder is fouling swap the carbs and see if the problem moves with the carb. That will tell you if it is a carb problem or something else. Riley
 

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Hey Big800, you definately have a carburation problem. If it's fouling plugs thats caused by a rich fuel condition. The first thing i would do(once you get it started for the day) is let it idle for about 3 minutes, Then kill it and check the plugs. I bet there nice and black. If thats the case, you may want to check your air screw adjustment, and check all your VENT LINES, to make sure their flowing freely. Check the needle/seats as well as the idle adjustment just to make sure that didnt come unscrewed. If it all checks out, maybe try rasing your needles a notch?
 
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