Newly rebuilt XP started once

[Zig]

We finally got to work on our 95 XP after the kids sucked up a tennis ball and sheered the brass rotary gear. Did everything to spec including torques. Put water to it and it immediately fired up and ran. Idle was pretty high so we shut it down to adjust the carb. Wouldn't restart. Gave it a quick shot of starter fluid. Thought I might have flooded it so I pulled the plugs and ran the motor for a bit without plugs. Tried to restart and it refuses to fire at all.
-Checked for plug spark, good.
-120 psi compression in each Jug,
-gave it a shot of gas in each cylinder,
-replaced the older fuel in the tank with new,
-cleaned the gas filter,
-replaced the gaskets in the carb fuel pump,
-made sure the oil tank was full,
-Battery is at 12.8V.
Any ideas? My next move will be carb kits but the fact that it wouldn't kick with a shot of gas directly into the cylinders makes me think its not a fuel issue?

 

[mikidymac]

Did you split the cases to change the rotary gear? You pressure tested the engine correct?

 

[Zig]

We did split the case. Replaced the gear assembly. Sealed the case and used all new gaskets. Funny thing is it started once and ran at a high rpm until we shut it off just won’t restart.

 

[mikidymac]

I would pressure test the engine as you should have.

 

[Zig]

You're right. One detail I didn't know about. I will check it now that I have my pop off tester. But why would the engine start right up and then not restart? Are you saying that the engine case may have lost pressure during the time that is was actually running?

 

[Zig]

You're right. One detail I didn't know about. I will check it now that I have my pop off tester. But why would the engine start right up and then not restart? Are you saying that the engine case may have lost pressure during the time that is was actually running?

What a great day! Put the carbs back on and gave it a go. Struggled at first but cleared its throat and began to run. Adjusted the idle setting and away we go. Thanks for your help. Hoping for a great trip to Idaho.

 

[Zig]

Just a short follow up. Got to ID. Put the ski in the water. No go. Found a great little shop out in the farm land and after just a few minutes they found both of my gas tank vents were plugged with mason bee mud. The tank pressurized in the 105 degree heat and forced gas into the carbs flooding the motor. Just when you think you’ve checked everything!

 

[mikidymac]

Unexpected but easy fix, good job!

 

[Zig]

Well, unfortunately that was only a temporary fix. Still had running issues.
So here’s the lesson learned. DO NOT USE NON MIKUNI CARB REBUILT PARTS!!!! The mechanic said the fuel pump was leaking fuel into the mag side of the motor, washing the piston and cylinder with gas causing scoring to occur which brought my compression down to 50 psi. New pistons, rings, a hone job and gaskets (both sides to keep things even)
Lessons learned tend to be expensive.

 

[WhiskeyD]

Make sure you pressure test the engine this time. I have a feeling you had an air leak all along and thats what burned up the new top end.