I went to start my go kart 5 hp 135212 model and when i did it trying running full thottle on its own i had to hurry up and turn it off fool with the throttle and the clutch but still the same.

if its a 5 hp engine fill to top of thread on fill hole

check for blockage ion the main jet and loose carby or bad gasket as you may be running too lean . Check float level is correct.

Try adjusting the L and H screws on the carburetor.
http://www.zamacarb.com/tipspage.html

there is two adj screws on the side of the saw below the primer bulb. get a small screwdiver flat or phillips depending on the brand, start saw with full thottle and start turning idle screw till you get it to idle then adjust from there

At full throttle does it sound like the rpms are up enough? There is a good chance that the govener is not set properly.

Had the same problem with the same engine. Governor control in the base of the engine fell apart. Requires pulling the engine which is pretty easy, then removing the bolts along the bottom of the crankcase. YOu'll see the governor and or pieces in the bottom. Use a magnet to get all metal pieces from the oil, then replace the governor. Get the model and type off the valve cover from the engine when replacing governor. 3 hour job and you're done..////While it's out check the valve lash by removing rocker covers. Set them at .006 or a tight 007. That way you'll know it didn't through a pushrod when it was over reving..good luck

the choke should be in the off position when running. YOU put the choke on to start it then when it starts u turn it off. If the choke is on the engine will die when reving

check the throttle position and make sure that its not stuck in the open position if its ok check the internal components of the carburator inside the flapper may have fell off , its usual held in place with a screw or 2. check the govenor and all springs

hows the compression ?

sounds to me that is flooded

turn off fuel an crank full thottle to clear gas

when starts to kick close thottle and turn fuel back on if stay running is fine if dies need to replace carb float needle&seat vavle

try these sites:

http://gokartguru.com/go_kart_building_202.php

http://www.usfreeads.com/1336701-cls.html

http://www.diygokarts.com/engine/go-kart-engines.html