Have a 97 MXZ 583. Was riding today and everything was fine,Shut it off to take a piss and now it won’t start. Only idles on 1 cylinder. Other side is getting spark and no fuel at all.Main line to carb is getting fuel. Took bowl off and everything looks clean. Any ideas?
runs fine when you open it up? I’d check the low speed jet on that cylinders carb to see if it’s clogged/frozen. doesn’t take much to do it. The mikuni’s on my 440 used to do that all the time in this fluctuating temp crap this time of year.
I’t dies when you give it gas. It barley idles on 1 cylinder.
Hmm, I’d honestly just take the carb off and clean it out regardless. Those Mikuni’/Keihin carbs are prone to debris causing issues. IIRC that’s a rotary valve motor, not a reed motor. Might want to make sure the valve is in good order.
There was a website somwhere that had PDF’s of the carb setting too. Lemme see f I can find it.
It is rotary. I was thinking somthing with that could be wrong also.
bingo, found it on top of google search :lol
your sled is listed little ways down in left column, carb setting down on right side a little bit after clicking it.
Another thing. I can’t remember if the fuel pump was a single or double chamber diaphram. Pumps typically run off case pressure change and if diaphram cracked, or a case seal blew, the pump may not be feeding proper fuel. Just somethign else to check that’s all.
I have a feeling it is a pump issue. I took the line off the carb and pulled the motor over. A tiny bit of fuel trickled out. I would think a good amount would come out of it?
yeah. Pull the pump off and check the diaphram. Also put a vacuum gauge on the vacuum source for the pump. Pull the engine over and see if the needle moves back and forth. That’s tell you if any seals are blown casuing a poor case signal.
dont buy a garbage sled, fixed
It was bought from a member from here. It ran great the first time I took it out.
id go with a air leak ,they were good for losin the pto side crank seal and lean out .or have no vaccum as they are a dual chamber pump prolly not enough vac to push the fuel
Also found the dead cylinder plug soaked in oil. I reset the carbs to oem spec, and still the same problem. I also found a small hole in the fuel line to that carb just by the inlet. Already fixed that though, and no difference.
Do they make a rebuild kit for the pump or is there something else better to swap in there? The thing runs great the first two times you start it up.
oil soaked plug in cylinder just due to no combustion. Oil injection pumping oil in but no fuel combustion to burn it off.
yes they sell pump reman kits. easy to do and cheap. Worth doing regardless.
You’ll still want to check the case signal to the pump. Like Jon said if there is a leak in the case the signal will be weak and the pump will not work right. Crank PTO/Stator seals can leak, as well as the center bearing seals which isolate the case halves. The pump’s work on the pressure differential created in the cases by the moving pistons. The outer two are pretty easy to change out, the center one unfortunately requires a teardown to fix. They usually don’t go bad though(the centers) unless you run them lean on oil or have an injection pump that’s out of whack
the MXz’s are great sleds. Wish I never sold mine('98 440 fan, and '99 600 liquid ) All this recent snow makes me wish I still had one. 
if the lines trickling you know you have a pump problem check the pulse line coming off the crank to make sure its not cracked or broke also check the brass fitting that goes into the pump its only pressed in and they come loose and last but not least if you really end up needing a pump I know deffinitly know where you can find one reasonable and used
if its loadin up with oil and its not premix the oil pump may need to be adjusted and its lettin to much oil into carb and or crankcase
The plug wasn’t soaked. You could just tell it was oil and not gas.
if you want me come take a look at it I can do that too
Yea it was just oil, no gas. So thats how we came to the conclusion that the carb wasn’t getting any fuel at all on the one side.
Is it common to only see fuel in one cylinder when the fuel pump fails? Or would it just run shity on both?
Frank, I would say for the $17 shipped this one would cost you. Just go ahead and replace the pump.
hey man, I just saw this thread.
If you drain the carb, then pull it over a bunch of times is there fuel in the float bowl? The float or needle could be stuck and not letting fuel into the carb.
Also, if you hit the primer will it start running on both cylinders? If not then you have another problem.
I highly doubt the fuel pump is the problem.
I’d be happy to take a look at it for you also.