Shurflo OnDemand Diaphragm Pump 28 GPM 12 Volt 12in "7a" Questions

I have a Snyder Industries sprayer for and ATV with a Shurflo Diaphram Pump 1.4gpm, 12V 7A 60 PSI. Seems to run ok, when first spraying it flows well then turns to a trickle or drip....I have ...