No power/acceleration in the water

[Alexh886]

My 1994 gtx has no power and will not even begin to get up on plane in the water. It starts and revs pretty freely on the trailer. I have all new fuel lines, fuel strainer and selector valve bypassed with a line running from reserve port, it sucks fuel right up to the carbs (I have a clear piece of line on the supply), the previous owner claimed he rebuilt the carbs and he gave me mikuni boxes with spare parts so I’m assuming he used those. I also opened them up and they looked fairly clean. It has about 145 psi of compression on each cylinder. It will idle around and move about 5mph in the water but if I try to go past 1/4 throttle it wants to bog and die. It has about a 3/16 hole in the muffler, only found this because I had a couple inches of water in the bottom of the hull. I figured this probably wouldn’t cause my lack of power though. I just replaced the spark plugs as well. I would appreciate any advice.

 

[hingstin]

Check the returm line, is it coming out fuel there when You run the engine. ( to be sure You have fuel delivery OK)
If You pull the choke, can you manage it to rev a little more then in water, playing around with throttle and choke to try to get it to rev up a bit...?

 

[mikidymac]

IF you are leaking exhaust into the hull it will choke out the engine.

 

[Alexh886]

IF you are leaking exhaust into the hull it will choke out the engine.

There’s a hole in the water box. Water is coming out of it. I assume that means exhaust is as well

 

[Alexh886]

IF you are leaking exhaust into the hull it will choke out the engine.

Rotary valve cover clearance is .018+. That would explain it, correct?