Engine dying under throttle

I have a gazelle 60cc engine with a Tillotson HL334B carb. I recently rebuilt the carb because of air bubbles leaking out from the carb side. New spark plug and fuel system. It now idles but cannot accelerate under load/ rev high rpm. Any ideas what to check? I’ve been messing with the jet settings and had no luck.

I don’t have experience with this exact motor, but simple 2 stroke carbs such as this one are basically the same in their operation. If you can’t find a baseline setting start with 1 turn open on each needle and adjust from there. This video gives you an idea of what you are looking for.

1 Like

A few questions…

What did you replace in the rebuild?
Did you test pop off pressure after you were done?
Does the lack of acceleration seem to be from no fuel delivery, or too much?

It’s not super unusual to have bubbles in the line periodically.

I replaced everything that came with the rebuild kit. The lever pin was the only reused part. I did not check popoff pressure. Lack of accel feels like too much fuel but not 100% sure.

There’s two kits. One is diaphragms only. The other has a needle and seat.

If the needle and seat are not working well or pop off is set too low you’ll get too much fuel.

Have you double checked you have the gaskets the right order