i just got a 98 xplorer 400 4x4 and i had it running pretty good the first day! so i ended up taking the carb off and cleaning it that night , the next day i put the carb back on and i couldnt get it to start after a while of cranking, i sprayed some starting fluid and it started, i killed it shortly after and then couldnt get it to start again even with starting fluid kinda seems like it was flooded. it has 120psi of compression and has a good blue spark
any ideas of what could cause this???

 

Open the 10 mm crank case drain plug at the bottom of the engine and see if you have a lot of gas pouring out. Plus did you just clean the carb jets only? Did you replace the needle and seat? Plus you can have fair or good compression,but if crank seals are leaking ,will have problems starting. If it's a seal, usually the one behind the front clutch. OPT

 

i will check the drain plug tomorrow morning and ill let you know! i just disassembled the carb clean everything up with carb cleaner i did not replace anything yet but from the looks of the fuel valve it looks new!
and is there any way to check the lower end seals?

 

Look carefully against the inside walls of the needle valve seat with a flash light. If worn you can usually see score marks along with worn, shiny edges on the float needle itself,plus the rubber tip will sometimes have a worn area around the tip.Plus another area is the float pin wear,especially if the float arm is loose and wobbly. A lot of people just clean up carbs,but since you're in there just replace the needle and seat! You can't always tell how worn by simply looking at it plus you don't know how long it's been in there (could be the original!) and they are not that expensive, just one less thing to worry about after you replace it.
Leak down test is really the best way to see if seals,base or head gasket is leaking,but you have to block the exhaust with expandable plugs and make an adapter for the intake along with a low pressure gauge. or buy a kit. We had the universal kit with a gauge and used a bicycle pump to pump up to 7 psi and it must hold this! You can also spray soapy water around the head and base gasket and carb intake. If no bubbles are present(air leak) but the gauge goes down,then it's usually seals. Lot of times you can pull the front clutch and actually see where it's been leaking around the seal. OPT

 

well i did a leak down test on the carb like the service manual says and it will hold 5psi but the needle does appear to have wear marks! so i am going to get a carb rebuild kit and new gaskets for the motor just so i know there good the piston and cylinder looks good. the thing says it only has 600 miles on it and by the way the engine looked i would say thats true just the body is beat to hell i will let you know as soon as i get the parts on! thanks OPT you have helped me with everyone of my atv
another question! what would be the best way to clean the motor
none of the cleaner i use get it as good as i would like!

 

We used S100 cleaners at the shop. They have several different products from spray on foam total cleaner to engine cleaners.Lot of shops carry this or you can order online. Plus there are several products at auto stores and Wallyworld (Be sure they are safe on plastic,aluminum and magnesium!) But the best thing to shine up dull looking plastic is Pledge furniture spray! Makes old plastic look new! We used this a lot! OPT

 

When it was running, did it smoke more than a normal 2stroke does? I had about the same problem with mine and it was the water pump seals leaking into the crankcase and killing the spark while tring to start. I replaced the seals and ran like a champ. I later had other problems but that fixed the starting prob....hope this helps....

 

well it did seem to smoke a lil more then normal but the owner before me
made it a pre mix and im not sure what ratio he mixed but i did pull the motor out and didnt notice anything that looks wrong and i will replace the gasket but dont wanna rush with the motor so im going to take my time building it and just swap in my other 400! one question is the other 400 motor is out of a 98 scrambler 2x4 but the wiring coming from the stator is different! now could i just swap my stator of the xplorer motor and put it on the scrambler motor so i can install it in my xplorer and ride till i finish built the other one???

 

You can do this,but make sure you line up the stator plate to the mark on the engine case. If its a 98 400 two wheel drive then it should be a Sport400 not a Scrambler!! The main difference in the wiring is because one 98 motor is two wheel drive while your explorer is 4 wheel drive.The motors are basically the same,carb numbers are one number off from each other(if it is a Sport 400?) basically jetting,etc,but you should be able swap over. Air box setup is different too on the Sport and Explorer,but should be able to mount up. I wasn't into swapping motors,just rebuilding what was there! OPT

 

ok i swapped everything from the 4wd motor to the 2wd motor and installed it and i positive i hooked everything thing up rite and i even double check to make sure no wires were cut or anything and when i hook up the battery i can here the starter relay clicking even with the key off and has no power so i disconnected the battery and like 3 seconds after i disconnect the battery it clicks again! and when i hook up the battery termanals is sparks like theres something pull power! any idea what this could be? i sure i just made some stupid mistake but i cant figure it out!