I just replaced my Walbro 255lph inline fuel pump and noticed that right out of the box it whines loudly and makes a screeching sound when its primed on occasion. Is there any chance that there is some kind of break-in period that the pump needs to work at 100% or am I looking at a defective part?
Thanks!

 

I replaced the fuel pump in my old Lincoln MK VIII with a 255 Walbro part and it didn't make noises so I'm going to say it's defective.R&R.

 

The pump will be louder than a good stock one. If it is a stock in tank pump it doesn't prime and is always in fuel. If you hear cavitation something must be wrong with the pump or install.

 

It's normal. Thats why they call it Whinebro.

 

It looks like the pump will start whining loudly after its been on for ~15 minutes and at that time the PSI in my rails will have dropped from about 23psi down to 20 or 21psi. On occasion the pump makes a slight screech at startup which ust sounds aweful... Bad pump or whineboro?