Not Starting at all and there is a spark

U have a dirty carburetor strip clean and blow out the jets with compressed air and give the spark plug a wire brush and reset gap orso make sure plenty of petrols coming out of tap

If youre talking about the spring in the carbs. throttle bodythe answer is yes.
Inside the main chamber is a cylinder with a long pin ,this pin or needle goes to the main jet which governs the gas flow.
if the spring is missing the needle will be in the wrong position .
as far as the floats are concerned they teater on a set pin and are designed to float on top of the fuel in the float chamber.make sure they move freely and that there not rubbing on anything or bent.you might want to try some starting fluid to get things started then make your adjustments,after starting aduust the idle screw first.
a good formula for idle screw is turn the screw all the way in .
Then turn it out 3 and one half turns out,
good luck,Gary

Hi, from your question it sounds like you have an idling problem. To fix this you have to adjust the idle speed screw that is located on top of the carb. Turn that screw in (clockwise) for faster idle speed. Hope this helps. All the best and good luck.

Turn both screws CW to stops (lightly), then back out CCW 1-1/2 turns each. This is a basic setting and the engine should start and run. Allow the engine to warm up, then pull the throttle full on. Turn the H jet screw CW until the engine starts to speed up, but still 4-strokes. Proper adjustment occurs when the engine is 4-stroking, but immediately 2-strokes when cutting. This gives best power and lowest heat. Release the throttle and adjust L jet CW until the engine idles fairly well, but will allow the engine to 'follow the throttle'. Adjust idle speed screw so that the chain stops turning, but the engine continues to run. Hope this helps!

Try placing some fuel mix in the spark plug hole and try starting. It should pop a few times--if so, then concentrate on the carburetor and fuel supply. Check the fuel filter, air cleaner, and muffler for plugging. Check the condition of all fuel lines. Make sure that all carburetor fasteners are tight. Does the machine have a primer bulb and does it fill with fuel when pumped? Have the H and L jet screws been turned? If so, turn both screws CW to stops (lightly), then back out CCW 1-1/2 turns each. This is a basic setting and the engine should start and run. Pull the throttle full on after warm up and adjust H needle CW so that the engine just starts 2-stroking. Release the throttle and adjust L needle CW so that the engine idles fairly well yet allows the engine to 'follow the throttle'. Set idle speed screw so that the engine continues to run, but speed is fairly low. Hope this helps!

Try a squirt of starting fluid in the plug hole, replace the plug and try to start. If you get a pop or two, then you have fuel problems. Make sure you have fresh fuel mix in the tank. Check the condition of all fuel lines including the in-tank line plus the fuel filter for plugging. Check the muffler and air cleaner for plugging. Does the engine seem to have good compression? If everything looks ok, then it may be time to disassemble the carburetor, clean and re-kit it. Set both needle jet screws initially at 1-1/2 turns out CCW from the CW stops (lightly). The engine should start and run--allow to warm up. Pull the throttle full on and adjust H CW until the engine runs faster, but is still 4-stroking. The correct adjustment is for the engine to 4-stroke, but immediately 2-stroke when cutting. Release the throttle and adjust L CW for fairly smooth running, yet allows the engine to 'follow the throttle'. Set idle speed screw to stop the chain from turning at idle, but keeps the engine running. Hope some of this helps!

Try turning the L needle CW to stop (lightly), then back out CCW 1-3/4 turns. Turn the idle speed screw CW about 1 turn. Start the engine and let warm up. Set the idle speed screw so that the engine keeps running but doesn't pull the chain. Turn the L needle CW until the engine runs fairly smoothly, yet allows the engine to 'follow the throttle'. Make sure the H needle is adjusted at full speed for 4-stroking, but immediately 2-strokes when starting to cut wood. If the above idle mix (L) adjustment doesn't help, you will likely need to clean the idle jets within the carburetor. Hope this helps!

Check with an auto parts supplier for the correct spark plug number. Actually, any clean plug that fits the hole will allow the engine to start, but don't start sawing until the right one is installed.Try spraying some starting fluid into the plug hole, install the plug and see if it will pop. If the H and L adjustment screws have been played with--turn both to CW stops (lightly) and back out CCW 1-1/2 turns each. This basic setting should allow the engine to run and accelerate. If this gets it running, warm up the engine, then pull the throttle full on and adjust H for high speed, but 4-stroking. It should smooth out immediately when cutting wood. Release the throttle and adjust L for smooth idle, but rich enough to allow the engine to 'follow the throttle'. Adjust idle speed so that the chain just stops moving.

Does it have good compression? Is the muffler plugged? Is the spark plug wet after trying to start? If not, try a little starting fluid in the plug hole, and try to start. If you get a few pops, try resetting the carburetor H and L jet screws each 1-1/2 turns out from CW stops. It should run with these settings. Warm the engine up, then apply full throttle and adjust H CW until it runs fast, but 4-stroking. It should smooth out when cutting. Next, set idle L for fairly smooth idle, yet follow the throttle without lag. Adjust idle speed just below chain movement. Hope this helps.

If the bike runs then Top Dead Center (TDC) is not an issue. But to check piston stroke position, Remove the valve cap cover on the intake of the front cylinder. Remove both the spark plugs. Rotate the crank shaft untill the rocker arm starts to move. The piston is now starting down on the intake stroke. Rotate the crank further and the rocker arm moves in the opposite direction. The piston is now going upward on the compression stroke. Look at the marks on the flywheel. Rotate the crank untill the TDC mark lines up with the timing index mark. The front piston is now at TDC.

If your model has carbs then the backfire fix requires you to syncronize and balance the carbs.
SYNCHRONIZE THE CARBS
Remove the air filter and rubber fittings to allow you to see into the throat of both carbs. You may need a mirror to see inside. You need to be able to see the slides go up and down when you twist the throttle. Now turn the fitting where the cable goes into each carb such that there is just a bit of slack in the cable, 1/16" is plenty. Lock ONE of the cable adjusters down tight. All further adjustments will be made on the other carb.

With the motor turned off twist the throttle very slowly while looking at the slides. Both slides need to begin lifting at the exact same moment. If the slides don't raise at the exact same time then slowly twist the throttle until the locked adjuster slide just barely starts to move. Hold the throttle still and turn the adjuster on the other carb so that the slide on that carb just barely starts to move also. Now recheck the slide movement timing. Do this process until the slides on both carbs begin to raise at the EXACT same moment. Lock down the loose adjuster and re-check the slides.

BALANCE THE CARBS
Turn the throttle screw on the LEFT carb one half turn inward. Now start the engine and get it warmed up. With the engine running, remove the RIGHT spark plug wire. Adjust the idle speed on the left carb to the point where the engine just can't quite stay running and dies. Now put the loose spark plug wire back into place.

Now turn the throttle screw on the RIGHT carb one half turn inward. Restart and rev the engine. Next, remove the LEFT spark plug wire. Adjust the idle speed on the right carb to the point where the engine just can't quite stay running and dies. Now put the loose spark plug wire back into place.

Turn the idle screw on each carb EXACTLY ONE QUARTER turn outward and restart the engine. The engine will be probably be idling very fast. Adjust both the idle screws equally from this point to get to the desired idle speed. Congratulations, you have just balanced and synchronized your carbs.

Please rate this solution. Thanks sgtswampdonk!