2003 Suzuki Ozark idles but won't rev
 

I have two 2003 Suzuki Ozark 250s, both 2-wheel drive. Last time we rode them about a year ago, the red one was not running well, didn't want to idle, backfired a lot. The green one ran fine.

Fast forward...I ordered a carb kit for both of them, thinking the red one has some trash in a jet. Both of these ATVs have had little use and I've always ran the gas out after use (put an inline cutoff valve in gas line). I pull started the red one to verify it was still running bad. It will start and idle, but as soon as you give it any throttle, it dies instantly. Give it a little choke, dies instantly. Took the carb apart and it was spotless. Went ahead and cleaned all the holes with carb cleaner and blew everything out with compressed air. All new jets, main jet holder, and needles. Put it back on and nothing changed. Starts, idles (not for a long time), but dies as soon as you give it gas. Same happens when you put the choke on. It does the same thing when I try to run it turned to prime on the petcock as it does in the on position.

Not an air filter issue. It is clean and it does the same exact thing with no filter on it.

Thought maybe there was a float issue or maybe a damaged diaphragm, so I took the carb off the green Ozark and put it on red. Started up and initially ran normal and revved for about 10 seconds and then started doing the same exact thing. Starts, idles (not for a long time), but dies as soon as you give it gas. Same happens when you put the choke on.

So...not the carb

Thought maybe vacuum petcock was bad, but there's no gas in the vacuum line going from petcock to carb and gas flows freely when on prime. I even plugged the vacuum line at both the petcock and carb end and tried to run it with valve set to prime. Gas flows freely, but does exactly the same thing. I unscrewed the screw at the bottom of the bowl and gas flows thru carb and out bowl drain line when petcock is set to prime.

So, I'm assuming petcock is good?

Checked spark plug and it wasn't fouled. Reset gap, didn't help. Will swap plugs between Ozarks tomorrow but I don't think that is it.

Anyway, that he history and now you're all caught up. Scratching my head. Valves? These were bought at same time and have had little use. Suggestions?

Thanks!

I'm not a 4 troke guy but when I read on them, I hear a lot of "valve adjustment".

Could well be plug. I have been hoodwinked twice by people fetching a bike in saying there is a carb problem and messing about cleaning it, only to find there is nothing wrong and the plug was faulty. Standard procedure if a bike comes in running badly, is to check the plug, nose colour can tell a lot, then fit another plug, sometimes problem solved. If not, then you clean the carb out. Next on the list is a compression test, I usually do the finger over the plug hole one, and only reach for the tester if it feels low.

I'm in the same boat, 2011 Ozark 250 starts and idles with choke; but as soon as I give it gas it stumbles and shuts off.

I ordered a new $$$ petcock think its bad as in ON or RES no fuel passes even though I'm cranking and there is vacumn.

I drained gas thinking maybe its bad


​​​​gas s it sat for a year. New plug.

I used cheapATV parts web site to order petcock but it wont get here until late July.

Patrick

Check petcoke for fuel flow when engine providing vac

Patrick