94 XP idles but won't rev (pt 2)

[andy.262]

So I had another thread about this issue here 94 XP idles but won't rev but I kind of got derailed talking about ultrasonic cleaners....

So to recap - its a new-to-me 94 XP, it will start and idle, but give it any throttle and it will die immediately. While its idling it is shaking a bit more than I think it probably should be.

I have done so far:
- verified strong spark both sides
- compression check (140psi each)
- new fuel selector, fuel lines, water separator + o-ring
- rebuilt carbs using correct OEM Mikuni kits from OSD with new needles and seats, verified pop-off is correct, the same for both carbs, and not leaking
- carbs are in sync as best I can tell
- verified rotary valve timing (149 deg open, 65 deg closed according to manual)
- verified rotary valve gap according to manual (feeler gauge between rotary valve and cover)
- as a test, bypassed entire fuel system to run directly from a fuel can into the carbs

What am I missing here? What else could this possibly be? There's not supposed to be an accelerator pump on these carbs, right?

 

[MOONlitn]

try disconnecting the black/red wire between the MPEM and the coil. It is the rev limiter and caused mine to barely run. Keep in mind you will have to choke it to kill it. Just digging to find my problem also came across its possible for the crank to move between the journals so the cylinders can have compression but they aren't 180 degrees apart. Just a thought. Look into it and let me know.

I'd even try opening up the high speed screw and idle mixture screws some to see if it helps

I'm new to all this too and have a 94 GTX I am battling at the moment, won't run in the water. Starts hard but does start out of the water.

 

[andy.262]

I have actually tried disconnecting the red wire since posting this originally. No luck.

That crank theory is interesting though. If I were to put a long screwdriver in each plug hole, I should see one reach the bottom at the same time as the other reaches the top, yes? And if that's not the case, then I would need a new crank?

 

[MOONlitn]

I have actually tried disconnecting the red wire since posting this originally. No luck.

That crank theory is interesting though. If I were to put a long screwdriver in each plug hole, I should see one reach the bottom at the same time as the other reaches the top, yes? And if that's not the case, then I would need a new crank?

That is my understanding. This is what I’d read here. Check it then ask others to confirm