3000W Chinese Gensets Info.

Wgeorge11 wrote:
We didn't go south this winter, so old yeller (46540 Champion) has been sitting and waiting without fuel. Fired her up the other day. She needed 3/4 choke to run and couldn't clear her throat for full throttle rpms. Pulled, cleaned and blew out the carb and tank without effect. Any suggestion for a fix is appreciated.

Back when I taught a class in "Problem Solving" the text emphasized that the first step was to always understand the problem before attempting to resolve it. You then developed a plan based upon your understanding, followed the plan and if that did not solve the problem you went back to step 2 and developed a new plan. Of course, key to all of this is the first step - fully understanding the problem (which it appears you do).

Small engine carburetors depend upon the flow of air across the main jet tube that protrudes into the center of the carburetor to pull fuel out of the float bowl and into the engine. The main jet, of course, meters the amount of fuel that enters the air stream depending upon the speed of the incoming air. This air speed is regulated by the throttle butterfly plate.

The choke creates a stronger vacuum in the carburetor that literally pulls more fuel into the engine, making a richer mixture than when the choke is open.

When a small engine will only run with the choke on - or part way on, the mixture is too lean. The #1 cause of this is a restricted main jet. #2 is inadequate fuel in the float bowl from a sticking float needle or fuel supply. #3 is often water contaminated fuel that allows water to settle in the bottom of the float bowl where the main jet picks up fuel. And finally #4 is a vacuum leak due to a bad gasket at the engine or carburetor flange or simply loose attachment bolts.

It sounds like you have been troubleshooting in the right direction.

As a suggestion, follow the Wizard's advice and soak the main jet in solvent. If there is any gum or varnish in the main jet the solvent should clear it out. Of course, an obstruction from a minute grain of dirt won't dissolve in solvent and air pressure or a super small wire may be needed to open the jet.

I often remove the drain plug from the float bowl with the fuel turned on and a catch can underneath to as a method to judge the flow of fuel into the float bowl. There should be a steady "dribble" from the drain. Anything else indicates a sticking float needle or obstruction in the fuel line. These carburetors utilize a fixed (non-adjustable) float height position, rubber tipped needle valve and a machined metal needle seat (non removable).

Fresh fuel is also advised (not something stored over the winter). Try a gallon of just pumped gas to see if that helps.