93 Johnson 60hp Tracker surges or drops power like it's not firing on all cylinders

I have a 93 Johnson 60hp Tracker pro series. I just bought it knowing it had a surging issue. when running above 4000rpm for about1 minute it starts to surge or drops power like it's not firing on all cylinders - but no alarms are going off...So here are some things to be aware of: It starts easily and idles good (maybe little rough - not sure whats typical) It has 100psi on two cyl's and 95 on 1cyl. The oil side of the VRO was disconnected, all 3 carbs rebuilt and a new powerpack was installed by previous owners mechanic 2 months ago(I have receipt).
So, starting with the basics I cleaned and rebuilt the carbs COMPLETELY even though they were already clean, I replaced fuel filter and replaced primer bulb; I also tested the alarm buzzers and they do work. Also, my mechanic only had time to water test and check the ignition/timing system and it works as it should (he sold me carb rebuild kits).
Now some things did improve after rebuilding carbs, it's easier start and faster to plane but, as I approach 4500rpms its only seconds before it hesitates and surges...eventually dropping rpm's down around 2200. BUT, and this is important, When it starts to hesitate, if I pull back on the throttle to say 3000rpm and stay there for about 1 minute - I can reaccelerate back to 5 - 6000rpm without issue for a minute before the problem starts over again. Note: Slowly squeezing bulb about 30% every minute or so does seem to fix the problem, so I suspect it's an air leak or the fuel pump - I'm not leaking fuel so I don't know how to find a leak and I'm not sure how to test the fuel pump??? Any suggestions would be appreciated!!!

Re: 93 Johnson 60hp Tracker surges or drops power like it's not firing on all cylinde

I found the problem. whoever disconnected the oil side of the fuel pump neglected to plug the line...they actually just cut the hose right at the pump which allowed it to suck air. I removed the small piecw of hose, than cut a 3" piece of hose and put bolt in one side and slid two hose clamps on - than slid the open end onto the niple and tightened the clamp. It now runs WOT without any issue. I spent 4hrs on the lake running around without issue. Thank god for commen sense, without it I'd be broke.

Re: 93 Johnson 60hp Tracker surges or drops power like it's not firing on all cylinde

One thing I forgot to mention, after plugging the oil side of the VRO pump I went to put gas in it. Its a center console with the tank in the console and since it was the first time I filled it up I looked under the console to see the hose. Glad I did because the filler hose was leaking onto the tank. I went home and wrapped the hose with rubber electrical tape and sprayed some degreaser foam on the tank, then headed to the lake for 4hrs (good day). I mention this because while I assume plugging the oil side of the VRO solved the air leak and my problem with hesitation, I guess it may be possible the filler hose leak was also a contributing factor...?