Assuming all contacts are properly tightned:
with the motor running at full throttle, check the voltage across the battery.
if you have 12.75 - 14.5 Vdc, then your battery is bad, replace
Lower than 12.75 Vdc your charging system is bad, start with voltage regulator- (NOTE: with this one, your battery still could be bad but you won't know unless you have a known good charging system)
My guess, bad battery...
.
with the motor running at full throttle, check the voltage across the battery.
if you have 12.75 - 14.5 Vdc, then your battery is bad, replace
Lower than 12.75 Vdc your charging system is bad, start with voltage regulator- (NOTE: with this one, your battery still could be bad but you won't know unless you have a known good charging system)
My guess, bad battery...
.