Re: HP500 stalls when getting on a plain
 

Drained the fuel tank today and had the same problem. I didn't see any water so I guess I'll be replacing the fuel pump tomorrow. It's a very strange problem. It idles fine, I can rev the motor when I'm in the slip but as soon as I try to get it on a plane, it stumbles hard like it ran out of gas and comes back to life once the RPM's are down.

Is there anything else I should check before replacing the fuel pump?

Thanks for everyones imput so far.

Re: HP500 stalls when getting on a plain
 

Is there any way that you could disconnect the fuel line that goes into the tank or just use another gas line and feed it into a 5 gallon gas can and take it for a spin. That way you know your feeding it fresh gas from a separate container. Also does your fuel pump have the clear hose that runs up into the carb. I guess it clear so that you will know if it is bad because you'll see fuel going thru it.

Re: HP500 stalls when getting on a plain
 

As have been said, hook up a separate gas can + a fuel pressure guage and take it for a run. That will give you a clear answer if it is the fuel quality or something in the fuel delivery system.