Fatboy is still kicking my butt

Mike V

Mike V

Member
Put a new pressure switch on...that works now. I am using poly barb fittings, braided poly hose to water supply ( a bucket right now for testing purposes) I have a 5/8 kuri-tec hose plumbed directly to fatboy.....standard gun setup and proper orfice size nozzle.

Pump pulses when it is on and drawing water. My other fatboy did not do this, just ran smooth until pressure built up then it stopped. This pump goes "cheg..cheg..cheg..cheg..cheg" when the trigger is pulled. flow is good and you can't tell it is pulsating from the wand or the strength of the stream.


Is the pump suppose to pulsate like this? I have checked every fitting, tightened the hose clamp on the intake line...I can not figure it out. There are no air leaks....it seems to work fine, but it is pulsating and my other pumps do not do this...



Any thoughts?
 
Had the same problem with mine. The pressure switch has a weak spring in it.

Try cranking the pressure screw in a lil farther and see if that helps it.

I changed the spring in mine and been working good.
 
Open your balve valve all the way and let it pump open and adjust your pressure screw until it stops.
 
There should be a small allen screw adjustment on the pump. Turn it in first and see if it gets better, if worse turn it the other way until you get a smooth flow. If you change tips u will have to adjust it again.
 
Crank down the pressure screw.
 
It's been a while since I bought a Fat Boy pump but I will say it would help enormously if the supplier would include a basic instruction sheet besides the one from the pump manufacturer.

Maybe they do now. I know the pump is designed for multiple applications but a brief explanation of how the size of hose and nozzles etc effect the pumps operation would help. I'm kind of a back alley mechanic and could have easily burned up our first if I didn't understand what was going wrong as it came set. I also did not know once they are set they should be operated only with a full open valve. Restricting flow causes the switch to cycle pulling mega amps and blows fuses as fast as you can replace them. My old 5800 Delavan didn't do that.
 
You must log in or register to reply here.
Back
Top