I'm using a 1" brass gear pump hooked to a Honda gx120 (4hp). I started noticing trouble last month when I switched from sugar water to the mannlake syrup. In order to start the motor I have to first close the ball valve on the tote and after several tugs the motor will start up. It runs fine while the valve is closed but when I open it up and allow syrup out of the tote the motor starts to bog down and then just stops. I have a relief hose running off the pump back into the tote when I'm not feeding. Something I'm noticing in the relief hose is there's a lot of air being mixed in.
Is this a motor problem or a pump problem and how can I fix this?
It's been fairly cold here in Linden CA with the nights freezing and the day temps getting up into the high 50's.