ok if I'm not mistaken the Honda GCV160 describes the engine ONLY
Honda GCV160-AS1A. 5.5 H.P. New O.H.V. Design.
# Recoil Starter.
# 7/8" x 3.16" Crankshaft with Full Keyway & 2 Woodruff Key Slots
# Drilled & Tapped 3/8-24.
# Compliance Positive Stop.
# Shipping weight = 30 lbs
$199.95+shipping
but I belive I have a twin to it with a briggs & stratton and the problem I had with mine was the reed valves were getting stuck and only one side of the pump was working, this caused a low pressure in the gun and the soap exchanger will not work on low pressure. at least mine did not..
Is this a vertical Shaft motor?
if so the pump is under the engine mounted directly to the engine shaft.
DO NOT USE A HAMMER on this Pressure pump unit it has ceramic pistons in it and they break easily, trust me a piston replacement is almost the same cost as the whole new unit.
Is this a COLD WATER ONLY machine?
If so the soap exchanger is right after the exit of the pump and there should be a small hose attached 90°to this block there is a very small spring loaded stainless ball in a brass housing or it can be stainless steel.. look to see if the ball is stuck? spring is broken/missing or rotted
not much more i can do with out seeing the unit first hand.
if your not mechanically inclined try looking at a lawn mower service center or small engine repair shop...Texas has to have one on every other block.