need help- machine running a little rough

[protiller]

i can't get any power out of it....it seems to be flooding itself out....disassembled and cleaned the carb, fuel and air filters. if i let it idle it dies out. it seems to idle better with the choke on but one has to "feather" the throttle, as soon as i let off the throttle it kills. does anyone have any suggestions as to what the problem might be? could it be as simple as bad gas?

[Fisher Dave]

It could be bad/old gas .. but it could be lots of other things.

What is this on?

It could be a spark plug, plug gap, choke, stator coil, secondary coil, spark advancer, air leak somewhere.... lots of possibilities.

I would change the gas and the spark plug and narrow it down some .. are you sure you got everything cleaned out in the carb?

[CHOPPERTHEDOG]

Sounds like you might have a clogged pilot jet. Did you clean it while you had the carb apart?

[Benny]

I have to agree with chopperdog,my street bike was doing the same thing last fall and this spring.Larsons took the carburators off and cleand them out real good to get it running with out using the choke.

There may be some varnish from the gas after sitting any time.So I would recamend soaking the carberator in carb cleaner for a few hour.

Benny

[protiller]

thanks guys....i'll take it (carb) off again and check the pilot jet.....yes, the plug is new....the only thing i have't doen was change the gas....thanks for the quick replies...any additional info would be greatly appreciated
-tiller

[shadyzr]

I had a 1992 polaris 250 trail boss that something simular like that happened. On the throttle there is some kind of a little switch button when the lever was released the engine would. I can't remember what that switch was called. What year and make is your ATV???

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"THE LANDING STRIP"

[Dave]

I agree it sounds like a carb problem.

shadyzr, you're talking about the throttle safety switch.

[Fisher Dave]

It sounds like the carb to me also .. but dont jump up and down until its running right.

We were trail riding on Sunday and had a very similar problem with the 3 wheeler ... turned out the secondary coil wasnt grounding(to frame) properly .. It was fine until it got wet... then it was the exact same symptoms as described ... not saying all atv's are the same, but a 4 stroke is a 4 stroke.. and the ignition system can do some strange things.

[protiller]

My brother says I have the wrong ratio of fuel and oil. It's a 250cc Suzuki Quadrunner....Aanyone know the correct ratio..24:1.....50:1?

[Benny]

Is it the QuadRUNER or the QuadRACER?
The quadrunners were 4 stroke motors and don't use oil in the gas.The quadracers were two stroke and do use oil premixed gas.
A ratio of 20:1 should be fine, but I would recamend a ratio of 32:1.BUT, be sure to check the plug to see how the gas/oil is burning.A light tan color on the plug is fine, a white color is to lean, a dark almost black to black dripping oil is too rich.

The 4 stroke plug would be a light tan almost white color, but you shouldn't have to worry about it to much if the carburator is adjusted to specifecations.

Ignition problems do not have any thing to do with a machine needing the choke on to run.
By having the choke on your restricting the amount of air that the motor will draw in, and allows the carb to suck more fuel mix into the motor.This can cause a rich or to much oil/ gas mix in two strokes .There for causing the plug to foul and lack power to move the quad.It might seam as though your at wide open throttle but no power to get to speed.Even some mis fire or engine conking out.

In a 4 stroke this can be deadly to a motor, as your actually adding raw fuel to the motor and it can run hot and burn valves.

I would still stay with the bad gas or pluged carb, but if that fails to help then look at the electrical aspect.
Almost every electrical component can be tested with an ohms meter.
Buy a good shop manual and a good quality meter and test the stator,coil,rectifier, and the CDI box if it can be tested.

The Honda 250R CDI box can't be tested with an OHMs meter, it just needs to be replaced with a known good CDI to see if that's the problem.

Good luck, Benny

[Benny]

Protiller, I mis read your question the first time.I thought you were refering to the machine not running or starting with out the choke being on.

Most of the advice I gave will cover the problem to a certain extent.

But I think you could have a bad stator, or CDI if it has the CDI vs the older magnito ignition.CDI is Capasitator Discharge Ignition by the way , not sure you knew that.

But as I said in the last post, try cleaning the carb again.
Then try testing the electrical componants.

Benny

[This message has been edited by Benny (edited 04-07-2004).]

[big trav]

i have fixed this problem on many snowmobiles and atvs about 95% of the time it is a pluged pilot jet or a pluged passage in the body of the carb.the new gas you buy goes bad and leaves deposits in your whole fuel system if not treated with "stabil" when the machine is not run for long periods of time. good luck

[Fisher Dave]

If the machine has a CDI unit (I origionaly assumed it did because my 81' machines already had it)... The component that rotates in the center(looks kind of like a rotor/point assembly) is your spark advancer. If your spark advancer is not operating properly your machine will be way out of time .. or firing too early, or late .. which will cause a loss of power, running rough... it can seem like your machine is flooding or your spark is weak.. but in fact its *bad timing*... it would have the same exact effect if you turned the rotor in the distributer of your vehicle 20 degrees .. it might run, but its not going to run well.

The weights on the spark advancer units are retained by springs at each end and force your timing to advance as rpm's increase.

You should be able to test the resistence of your stator coil with an OHM meter .. If specs say its supposed to have a resistance of 215-240(example) and you get a slightly lower reading (200) .. there should still be ample power and I would look elsewhere unless you get a very low reading.

CDI's cause a lot of problems. If you can get a hold of a good manual for specs most the individual ignition parts can be tested with an ohm meter.

[sledhead]

Its does sound like the machine still has a plugged pilot jet, If your cleaning the carb, you got to remove the jets and run a wire through them. Also let it soak in carb cleaner, the spray carb cleaner through all the curcuits. Then blow them out with compressed air. If it seems more like it is flooding out even if everthing is squeeky clean and runs better on choke, you may have a bad needle and seat. If I remember right some susuki's can only get a new needle. To get both you would need a whole carb. If this still doesn't solve your problem start looking towards compression and leak down. You may a a lot of blow by and the motor needs refreshing. just my 2ct's.

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ride safe, wear a helmut, stupid hurts

If you get'em serviced, wash'em first.

[protiller]

Last week my brother took the carb and diaphragm off and cleaned them. He said it runs better, but still not perfect. So, I took it out for a "test" drive up and down the road. He was right it ran better, but was still spitting and sputtering. Then all of a sudden it took off and I had all kinds of power, then none. Then it killed and now we can't get it to fire. We pulled the plug and there's spark. So I assume it's not an ignition issue. Thinking it's a fuel issue I sprayed starting fluid in the carb and it kinda fires, but not like one would expect with starting fluid. I'll pull the carb this week and recheck the pilot jet. I'm (we're) getting extremely frustrated. Thanks to all who have contributed, your input is greatly appreciated.
-Tiller

[This message has been edited by protiller (edited 04-12-2004).]

[protiller]

Two more questions....if I check the resistance at the various checkpoints does the machine have to be running or does the key only need to be turned on? And if it does need to be running....can I have someone push the starter button and while the engine is cranking test the various components?
Thanks
-Tiller

[sledhead]

If you checking the ohms resistance on the ignition coil and and stator the machine doesn't need to run or be turned on for those two tests. You have to unplug them from the wiring harness so the machine would not run any way. but if your doing a peak voltage test then some machines require them to run or aleast turn over. Also you never mentioned if it is a quadrunner or quadracer? what year is the machine? I could look up some specs in the manuals at work for ya.

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ride safe, wear a helmut, stupid hurts

If you get'em serviced, wash'em first.

[protiller]

Thanks sledhead,

1987 Suzuki Quadrunner 4x4 250cc

[Fisher Dave]

protiller...

Your machine can shoot a lightning bolt off the plug and it wont do you any good if it fires at top dead center (example).

When you have visual spark its usually enough to keep the machine running.. the question is... is it sparking at the right time?

[CHOPPERTHEDOG]

Also... check the rubber carb mount between carb and jug to make sure there are no cracks. Have seen where this causes a problem and it is easily over looked because the crack isn't obvious without actually flexing the rubber mount.

[Dave]

Been thinking about this. Another thing to check is your exhaust flow. I had a Yamaha Warrior that acted something like your machine. The packing in the exhaust was falling apart and at times, clogged the exhaust and would kill or barely run. Pulled all the packing out and it ran perfect. Just another idea to check.

[viking605]

I have a 04 sportsman 400 and mine had similar symptoms as yours I brought it back to the dealer and they took carb out and cleaned it and adjusted the clutch its like new again it even seems to have more snap then when I got it

[sledhead]

I'll Check some specs when I get to work on monday. All the above sugestions are good ones. If you can't find anything more wrong with the carb or fuel delivery, and the intake boot is not cracked. It could be time for looking at compression and leak down. I have seen where if there is zero valve clearance on the valves she not gonna idle. and will back fire and run poorly. also fisher dave has a good point is it sparking at the right time. The machine has CDI igniton so ther are no points. But it could have a sheared flywheel key and the rotor spun on the end of the crank. You would have to pull off the stator cover to she if this is the case. but for now I would go for a valve adjustment first. Don't need to buy any gaskets for that.