2000 gtx mid RPM Bogging

[Chris7766]

Here is the background info 2000 gtx with 951 carb motor. ski has 120 hours on it with an sbt motor that has approximately 50 hours on it. I bought it with burnt pistons clearly from a lean condition. replaced the top end with 1.00mm over pistons and sleeves. rebuilt the carbs which were really clean. I replaced all fuel lines with tygon line. I also decided to inspect the crank since I couldn't find a reason for the lean condition. One of the springs on the Mag side crank seal (outside spring was laying in mag cover case) had broken and was allowing air to be pulled in through the mag cover causing the lean condition. The crank was in excellent shape and all bearings checked out great. (SBT uses a ton rtv on their crankcases, not a big fan of this.) I cleaned everything back up removed existing sealant resealed with Permatex motoseal and torqued everything back to spec. I put the motor in and on the hose it fired right up after priming everything. It revs great on the hose idle was set to 3000. Took it to the lake and from closed to about 1/3 throttle it does fine in the 2/3 range it wants to bogg and die. if your at idle and hold it wide open it will slightly stumble then take off and runs great at top end turning 6950rpm. The plugs looked great after a full throttle chop and cut. So does anyone have any insite into what is causing this bogg in the transition slot from low speed to high circuit?

Carb Specs: All Stock
N/S 2.0
Pop Off 22 psi. with original springs
MAIN-162.5
PILOT-75
Low speed 1.5
High speed 0

I turned out the low speeds to 2 turns and this resulted in a lazy return to 1500 idle so I plan to go back to 1.5.
I plan to pull the carbs back off double check the jetting.

Thanks in advance for your time, I've been working on skis on the side for a few years now, several top ends and carb rebuilds, and generally don't have trouble setting up carbs but this one has me a bit stumped.

 

[garrettb]

Check your throttle cable adjustment. Make sure the butterflies open all the way at full throttle.

I'm curious how you have 22 PSI pop off. With the factory "dull silver" spring, and the 2.0 needle, you should be at 25.

 

[Chris7766]

I did confirm the butterflies are opening all the way, I misspoke on the 22 it was closer to 23-24 I apologize. It's early here.....:facepalm:

 

[garrettb]

Are you using your stock airbox? It's a pain to put on and take off, but it's important in making sure the correct fuel/air mix is delivered.

 

[Chris7766]

Yes Sir, Stock air box with the plastic ducts is installed.

 

[Chris7766]

Just realized I postes this in the sport boat forum I am going to move it to the PWC Forum