Welcome to the forum.
Correction; when you open the throttle, you are giving the engine air. The job of the carburetor is to meter the correct amount of fuel with the air to create a combustible mixture. If it dies when you open the throttle, it is typically giving the engine all air and no fuel.
My first guess is that either the fuel tank or carburetor is not venting properly and the fuel level drops inside the carb as the engine heats and about the same time the engine gets hot, it runs out of a sufficient supply of fuel inside the mixer. Another possibility would be a fuel line or petcock damaged by alcohol and partially clogged with swollen rubber. Heat from the engine could cause the rubber to expand and shut off fuel flow until cool again.
A quick test might be to choke it as trying to throttle up - if it will accelerate with the choke on vs dying with the choke off, it confirms the lean condition hypothesis.
Correction; when you open the throttle, you are giving the engine air. The job of the carburetor is to meter the correct amount of fuel with the air to create a combustible mixture. If it dies when you open the throttle, it is typically giving the engine all air and no fuel.
My first guess is that either the fuel tank or carburetor is not venting properly and the fuel level drops inside the carb as the engine heats and about the same time the engine gets hot, it runs out of a sufficient supply of fuel inside the mixer. Another possibility would be a fuel line or petcock damaged by alcohol and partially clogged with swollen rubber. Heat from the engine could cause the rubber to expand and shut off fuel flow until cool again.
A quick test might be to choke it as trying to throttle up - if it will accelerate with the choke on vs dying with the choke off, it confirms the lean condition hypothesis.
