300 premix fuel problem

[chad.r]

I have an 1998 300 promax. serial number 0G787014 model PM300L. This motor was installed on an 21xdc last week so therefor some adjustments are expected. i took it out for the first trip and i noticed when i pushed hotfoot fuel pedal wide open the motor would start missing and almost quit. However i could let off the pedal maybe to 3\4 and it would take back off and everything seemed normal. My question is there an adjustment procedure for timing or adjusted my fuel linkage. What Ive done so far was had someone hold fuel pedal wide open and i set the set screw to were the butterflies looked to be centered. Before when the pedal was wide open they were past center or 90 degrees. I know this is not correct exactly and I'm assuming there is an ohms number or range that the throttle position sensor should be at for correct WOT. Any advice is greatly appreciated. Note i did not mess with the butterflies timing just the throttle cable from hotfoot to engine, the setscrew I adjusted was were the throttle cable hooks up to throttle linkage.

Today I took boat back to lake after I centered the butterflies out an WOT and it seemed to run fine, however after I run a few miles i would start missing almost like it was running out of fuel. Once again i could let of fuel pedal after a few seconds I could give it gas again and it would take back off. While running I noticed my voltage was low at the depth finder, it dropped down to 10 volts. Im going to check voltage at alternator and make sure I just don't have a voltage drop due to an corroded wires or a bad battery, but my question is who sensitive is this motor to low voltage? Thanks

Also this motor has an MAD EFI throttle body installed on it.

To follow the rules of forum:

Im running an 27 pitch trophy plus, Ive turned it to 5500 or so rpms, have not got to a big enough lake/river to stretch it out. I have analog gauges and water pressure at WOT is around 18 to 20lbs on a sport master lower unit. Thanks again