why won't it go

[BigSlant19]

Hey all

I have an 84 champ with a 99' johnson gt200 v6. I inherited this boat barely running. I have since replaced the steering cables,put on a larger prop, 14.5x24, changed the plugs, fuel lines, replaced all the floats, needles, gaskets in the injectors. The motor starts right up and I can idle the gas tank dry if I wanted it sounds great and will go forward and reverse just fine. Then when I'm ready to go and throttle up it does either one of two things, sometimes it just stalls out and sometimes it will go but with full throttle it is hard to to plane out. If I have a passenger I can put them on the bow and when it finally gets on pad I can trim up and it gets to about 50mph at 4100rpm at top speed. I would be incredibly satisfied if that boat can pop up and get to 50 always. Sometimes it feels/sounds like the prop is cavitating so I let off and try the hole shot again. The motor is transom mounted, I've been toying with the idea of a Jack plate but set back size and price deter me from jumping on this if there is something I'm missing. Please help

[Rebel Sympathy]

"....put on a larger prop". Obviously the engine is lugging. Sounds a lot like you have way too much prop for your combination. Of course, it can be something else....

[BigSlant19]

Thanks for the reply Rebel. It started with a 14.5"x19 aluminum and had the same problems. I also tried a 14"x22 4 blade ss prop. Same problems. When I get it on pad it goes pretty good. Just takes awhile to plane out if it doesn't stall before. I've been reading a ton of other forums and sounds like maybe stator and power pack?? Sounds like a lot of these motors have similar problems. I appreciate the feedback.

[BigSlant19]

I should mention this boat is 20'6"

[BigSlant19]

And so far with all the prop combos I have used wot is pegging at about 4200rpm but the difference in speed on gps between each prop is about 8-10mph. I feel like this motor should be spinning faster. I'm scheduling to bring it to a new mechanic on Monday but with the budget money I'm prepared to spend I would almost prefer to use as a down payment on something new!!!

[BigSlant19]

And so far with all the prop combos I have used wot is pegging at about 4200rpm but the difference in speed on gps between each prop is about 8-10mph. I feel like this motor should be spinning faster. I'm scheduling to bring it to a new mechanic on Monday but with the budget money I'm prepared to spend I would almost prefer to use as a down payment on something new!!!