Hi, new to forums.. this atv however is challenging my patience.

I picked it up for $5, not running. It is actually a clean, solid quad. It obviously wouldn't start, so I checked the compression. Low. Put new rings and piston in, cleaned up the cylinder some. 115 psi HOT and COLD now!

Still wouldn't start, found left crank seal displaced. Put new one it.

It fired up immediately! It ran like a solid two stoke.. for 5 minutes. At that point, it starts to lose it's idle, get kinda blah blah ish, then boom.. it's out. I can restart, but not for long. Let it sit for 5 minutes and the whole cycle repeats.

Plug color actually looks perfect. Electric choke seems to be working. I cleaned and inspected the card 100x, it actually looks good. Like I said earlier, the compression is 115 hot and cold, the spark looks great. No air leaks from what I can see.. the carb boot looks great, all cylinder bolts torqued.

Again, when cold/warm it carbs like it is fuel injected! Strong clean running atv.. but after 4-6 minutes.. the idle starts to get sloppy then it just bogs out and dies.

The stator ohmage is a little off, but not too bad.. the coal ohmage is a little off as well.

If I manually choke the carb (by plugging the intake OR covering the left venturi hole on the carb opening, it springs back to life for 30 secs or so.

Please advise! A chinese dealer in OH seems to think my stator is bad.. but I would think choking it to bring it back to life would indicate something else?

Worn reeds? They actually look pretty good and clean. Right crank seal bad? Bad stator? Help!!

Oh, and thanks!

 

I know nothing about two strokes, so I most likely cannot help. But your same symptoms for a four stroke resemble a quad where the choke (actually a bystarter valve) is not working.

So I'm wondering what criteria you used to determine that the "choke - i.e bystarter valve" is not working....

 

have you verified the float level? running for a few min., then coming back to life when you block off the air sounds like it is running out of fuel possibly. Also, 115 psi is ok, but not fantastic, might be time for a one over bore (which also means new bigger piston and rings,sorry) I would think a leaking crank seal would suck air, which usually makes a 2 stroke rev uncontrollably, but i could be wrong ( I work on a lot of sleds, not so many 2 stroke quads) when it starts to run bad, try spraying carb cleaner around the intake and near the seals, if the idle picks up, you could have a leak there.

 

Float level.. well, about the only thing I verified was that it shut off when the float was "level". I can't find a float height spec anywhere, so I don't really know what it is. I do agree somewhat with you as I have a clear fuel line on the carb. When I plug the intake of the carb, you can suddenly see it suck in 1" or so of fuel out of the line, almost like the bowl is empty. I can check the float level, I just wish I knew what it was supposed to be? Plus, would it run great for the first 5 minutes or so with a low level?

Electric choke.. I've got voltage going to it, and when I replace it with another (more beat up looking one that I have) it runs like crap. Also, when the engine is warmed up, and I unplug the choke, it runs like crap. So no, I can guranatee that the choke works perfectly, but that is about all I can do? Thanks!

 

Agreed. Your further data does not indicate a bad electric choke.

 

Update..

The carb circuit that I could plug to make the atv run better or keep from stalling was the left-most hole in the front. This circuit is connected to the air/fuel mixture screw, which appears to work it's way into the float bowl area. If I plugged this hole when the bike was going to die, it would bring it back to life for a little while. I had this screw set at 2 turns out.. so I thought why not screw it in almost all the way? I set it at .5-.7 turns out and rode the atv for 10 minutes, no issues.. unforntunately I had to leave. But I will try again today. Not sure why I would have to turn it in so far, but now I am convinced that I have a carb/fuel issue..