92 200 hp johnson cutting back when warm

[BASSBOAT21]

Here's what I have ----this engine ran fine when first trying out--than after getting ready to fish and move it started cutting back bogging down----would not take the gas hold it to the floor and would not go----let it rest a while ,fished a little, cranked up fine and would take off and haul ***---but doing this there was a feel like it wasn't fully powered----loaded the boat up took home----found out upper motor mount was broke{has nothing to do with way it was running bit I know what the shaking was}put engine in 250 gal test tank cranked and had a tester for spark on all cylinders all fire but some were steady fire others were flickering fire --the fire was red----before I done this I checked compression engine warm--all 90 psi on the dot---water was pissing fine---when engine running----also when we had the boat out the warning buzzer came on steady hard buzzing sound--water pisser was still pissing great----what could be wrong ----pickup and stator---fuel pump----restriction in gas or lack of gas---the vro on this motor has been disconnected for many years original owner told me---I am mixing it 50-1--evinrude oil ---for older model tw3-thats what he used-------any suggestions all help would be greatly appreciated