I have a 1991 Trail Boss 4x4 and a 87 Cyclone 250. They are both doing simular things.
When I very first picked them up, they'd fire up on starter fluid for a couple seconds.
Both have strong spark, clean carb's (now), fresh gas and 2 cycle oil, new fuel lines and filters and I'll assume good compression since they fired up for me.

When I first got them the carb's were varnished up, but now that the carb's are clean and set (idle screw 1 turn out) now they will not run. Still have strong spark. Plug's are getting wet (even saw fluid dripping out of the exhaust), and I think it's oil fouling it out. I put a lighter up to the plug and it would'nt burn off. Even after waiting a few day's and letting it dry out, would'nt fire back up. Now it wont fire up with starter fluid either.

Is it common for the oil injector to fail and over oil? I did use some pre-mixed 2 cycle gas that I allready had for my boat, since the atv's are old and I did not know if the oil injector worked still or not, I did'nt want to take any chances so did'nt think it would hurt to use premixed fuel with the stock oil injection.

Help please!

 

Check compression and if that is over 100psi check the exhaust for raw gas or blockage

 

<div class="FTQUOTE"><begin quote>Originally posted by: ftwflh

Check compression and if that is over 100psi check the exhaust for raw gas or blockage</end quote></div>

If the compression is bad, how can it run on starter fluid?

 

It fire easier than gas.Best to check it anyway.also check the pipe

 

<div class="FTQUOTE"><begin quote>Originally posted by: ftwflh

It fire easier than gas.Best to check it anyway.also check the pipe</end quote></div>

I'll check the compression as soon as I get my compression gauge back. But, it fired up on starter fluid 2 week's ago, and now it wont, so I'm leaning more twards flooding, or fouling out from the oil.

 

when the cab floods it can fill the pipe up.Had this happen more than once

 

Will a 2 stroke run with the pipe removed?

 

not very well

 

no because there is not bottem end torque. i agree with the compression. i would try a leak down test too. you might have a bad air leak somewhere. if the motors have been sitting for a while then it wouldnt suprise me if there was a leak.

 

alot of times even a flooded engine will fire up on starting fluid as it has a very high flash point to ignite unless the plugs dont fire all the time. agree to check compression to rule it out. if the plugs are real wet then you know its getting too much fuel, unless the compression is bad then it would still flood it self not being able to start but still pumping the gas in. imo.