8 hp honda on cement mixer starts on first pull but shuts down as if it is running out of gas. I put fresh gas in it and cleaned the filter and bowl of the carb.

Flush gas tank, fill with fresh gas and Stabil. Replace air filter. Remove bowl from carb clean bowl and holes in bowl screw.

Ensure fresh gas is in tank. Follow gas line from tank to carb. Have locking pliers ready to pinch off gas line or close gas line valve. Remove gas line from carb. observe gas flow to carb. Remove carb bowl from bottom of carb. Attach gas line to carb. Does gas flow to carb. Observe float, float down gas flows, float up no gas flow. If float is bad replace float assembly or carb. Remove float mounting pin and needle metering valve. Use a bread wrapper pealed back an inch so thin wire can clean out port of meter needle. Use wire to clean out center port. Observe bowl screw look for hole thru screw, clean out with wire if preset. Re-assemble carb. Clean replace air filter. Fill oil. 30w. Prime motor, pull rope 10 times to start. No start, replace carb.

This is sometimes caused by dirt or debris in the fuel tank, carburator float bowl or in-line fuel filter if it has one. When you start the motor the dirt is settled down and the motor runs fine. While the motor is running, the vibrations and fuel flowing through the system agitates the dirt and it eventually plugs the filter or jets. When the motor shuts down the dirt settles down and the process repeats. Replace the in-line filter if it has one and clean out the float bowl on the carb. While you have the fuel line off, let some gas flow through the fuel lines to flush them out. If dirt is a problem also check your gas can(s).

if you have gas to carb rebuild carb or relace

G'day, sounds a bit like the float valve in the carby might be stuck nearly shut or just some moisture in the carby, a light tap with the handle of a screwdriver on the side of the carby bowl should fix it if it's the needle stuck shut (happens from sitting sometimes), or maybe try loosening the drain screw in the bottom of the carby bowl to drain any water etc out, hope this helps :)

Look for plugged filter anywhere in fuel line.

So many possibilities, so little data... <grin>

When you say "clean gas", do you mean that you added "fresh" gas, or that you emptied the tank, and refilled it with "fresh" gas?

Try this:

a. remove the "float bowl" screw, and put a regular "bowl" or pan underneath to catch ALL of the gas as it comes out.

b. if the gas is totally "clear", then it (probably ain't the gas), but... if it's "yellow", it's old and/or contaminated; alternatively, if there's any water (which may appear as a grey-ish liquid) then it's contaminated; also, don't forget to check the gas from your "storage" can, the same way...

c. re-install the the screw, and put some *FRESH* gas in the tank.

d. pull the spark-plug, and clean (or replace) it.

e. prime it, and crank it, and it should start right up.

the engine is not getting enough gas. when you hold down the primer you are bypassing this problem. to fix this simply adjust the carb's fuel screw, located on the side of carb, a little at a time until runs smoothly.

Here are a few things to do >>
How old is the gas in the gas tank? Get fresh fuel.
Remove the water trap bowl at the bottom of the petcock, (gas valve). Any water or trash in the bowl? Drain a cup of gas from the tank. Is there any water or trash in the cup? Clean the bowl and filter screen if present, then re-mount them, ( not all bikes have a water trap bowl or screen ).

Install a new stock NGK spark plug and try to start the engine. If the bike doesn't start and run properly then shut off the gas and remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. Remove the two screws on the outside throat of the carb and spray into the screw holes as well.
< < READ CLOSELY > >
Be sure to put these two screws back in the same hole they came out of. IMPORTANT > do not tighten these two screws down. Only screw these in until they LIGHTLY seat. Now turn each screw one and one half turns outward. Put the rest of the carb back together, clean the air filter and install the carb. Let the float bowl fill then start the engine. Set the idle speed with the idle screw.

I am uncertain if the bike has ran for you or not. "Did pull the spark plug and kick started it." If the bike still will not run then the cam chain may be out of time. Why was the tensioner off the bike?

Please rate this solution. Thanks budx5!

had the same problem with my Honda engined mower. you can't see it easily, but there is a very fine screen in the outlet of the fuel tank that gets blocked and fuel will not pass thru it fast enough to refill carb. remove tank and pour fuel in another container . Use a flexible plastic tube in the outlet or make a small wire hook to penetrate the screen,or preferably, remove it. confirm that fuel flows freely thru it, remove any debris, and reassemble. Change spark plug, add fresh fuel,and test. best of luck!!!! Ray