95 GTX only goes about 10 mph

[GTXer]

Hi all,

This is my first post, so please be gentle.

Model: '95 GTX

Issue: slowly accelerates to about 10 MPH. Starts easy and idles great.

Work done: I have cleaned the carbs, the small filters in the carbs, the one in the line, replaced the gas lines, cleaned the fuel selector and even replaced the temp sensor on the engine.

Additional testing done: When off the trailer, runs like a scalded dog. When I run water through it via flush plug in back, it bogs down similar to in the water.

Unknown: Does the '95 GTX have RAVEs?

Has anyone experienced similar issues and what was the repair(s)? Any ideas/suggestions are greatly appreciated!

 

[wtrgrl]

Do a compression test

 

[DooWacka]

No RAVEs on the '95 GTX
Sounds like the carbs need adjustment. The Mikuni carbs sometimes/often need the "low speed" screws adjusted. Try 1 1/4 to 1 1/2 turns open to start then play with them until you get it to "transition" to the midrange jet. It sounds like you are stuck in the idle range. The screws have to be "felt" since they can't really be seen to adjust, and the MAG carb screw is the hardest to reach unless you have a long right arm, since you have to reach from the rear. Since you have had the carbs off to clean, you know where the screws are by feel, so you have an advantage. Adjust the carbs evenly of course. It's not unusual for it to run great on the trailer but bog down in the water if these screws aren't right. This gets more problematic as they get older, and the rotary valve wears more.
Do the carbs still have their paint, or has some come off due to gas leaking past the diaphragms? If so, did you check the diaphragms held up to a bright light, since small perforations aren't readily visible.
I'm not sure however why it should bog down when run on the flush plug, unless you're getting to much water in the tuned pipe.

 

[GTXer]

Thanks for the replies. Been a long weekend and hope to try both tomorrow night after work.