Well lemme try to make something sufficient then.
Yes, Magikarp In certain areas magikarp does outrange the man, however, with the one of Puleman's moves Lightning Dash, he becomes intangible from all enemies which I'm assuming would also mean all of the attacks. If he sees a hydropump heading his way, which he would considering the fact that the attack speed should be equalized as well as their normal movement speed, not only could he simply lightning dash out of the way entirely, but he could also dash trough the hydro pump in the first place, not becoming wet and therefor not becoming useless. Meanwhile hydro pump can only be used five times, or a max of eight if it's used up those PP boosting items. Assuming this Magikarp is wild that's not going to happen, so he can only use it around five times, and constant charging of a hydro pump in the first place would tire out a magikarp eventually.
Pulseman could even fly with his volteccer as far as I'm concerned, giving him more mobility, even if it is a bit uncontrollable, and he's still intangible to attacks while in this given state, meaning that hydropump wouldn't do much. Even if Hydro Pump isn't limited to five uses the magikarp is going to tire itself out from a massive attack which is surely going to tire it out, and not only does Pulseman simply have to dodge, but he also has higher stamina than the magikarp. All he has to do is continuously dodge with his Lightning Dash to injure and further fire out the opposing magikarp, who tires itself out by trying to dodge attacks and hit hydropumps since that's the only thing it can do without leaving the water. It may outrnage pulseman, but he can probably counter it.
There we go. Is that good?