Engine runs away at 7100 rpm

[cdnbikerdude]

Hi Everyone

I have a recently rebuilt carb i put on a 2002 GTX. Now when i start it (new gas lines too) The engine starts but within about 3-4 seconds goes to 7100 rpm and sit there till i stop it. I removed the lanyard one time and it didn't kill it either! I had to pull the choke closed to kill the engine.


Any suggestions? The throttle lever moves smoothly both WOT and off when the engine is not running.

Are the high and low set incorrectly? I didn't adjust the high i just made sure low idle was 1.5 turns from bottom. The idle "idle" is not forced in either...


I am stumpped....

 

[timmyboy76]

hey dude...recheck the throttle cable, take seat off, with not running, and have someone feather the throttle, see if it resits on idle screw, mess with screw as well, someting aint right there...:cheers:

 

[cdnbikerdude]

Just checked the throttle again and it appears fine.

If i push the throttle in it does make it get to max rpms faster so it isn't wired backwards or anything like that. But it will never come back to idle even though the throttle gates are closed again.

wow this is bizarre.

 

[cdnbikerdude]

After fiddling with both low jets to get it to start (if it was too far in the engine wouldn't start) it appears to be working now. I also took the throttle cable off and re-tightened.

I made sure they were both jets are set the same and they are about 1.75 turns from fully in.

I'm guessing once I put the air intake silencer on it will change again.



:hat:

 

[kustomkarl]

Be sure the throttle linkage is returning with a snap. The idle can only be adjusted properly in the water under load. Only use the idle screw to adjust the idle speed, NOT the low speed screws.

Karl

 

[cdnbikerdude]

Thanks for the tips guys... i've got it in the ball park idle zone driveway wize for tomorrow's long weekend here in Canada.


It's something to do with the low needle sets and idle which need to be done in the water as Karl metioned. 1.75 turns each needle gets me in the range right now. I'm either too fast or too slow testing in the driveway. I don't want to run it too long without being in the water to cool some of the bearings down below. (I had a flush hooked up)


I'll post what happens when i get back!

Photos are internal carbs on a 2002 GTX with 35 hrs.

Thank you everyone!