Only runs on full throttle

[roundhouse]

And it will only run about 2,000 RPM. Carb was just rebuilt by pro after I rebuilt it and it is no better than when I did it. Spark is fine. Compression is good (R 192 L 179). I do not think there are any vacuum leaks. Fuel is getting to carbs but I do not know how much.

Engine will rev up with a shot of starter fluid. So it is a fuel delivery prob?

I took the petcock apart and cleaned it out before trying any of this and it was in poor shape but is spotless and flows now. Could that diaphragm thingy have anything to do with it?

I just cannot for the life of me figure this out. Any leads would be much appreciated.

I am so close! dying to ride it!

[ducatiman]

2000RPM at full throttle?

is your cable freeplay allowing the throttle plates to fully close?

does the idle adjust knob have any effect? (turning down from your 2000RPM?
does the choke offer any aid to starting?

To confirm adequate fuel flow...each bowl should contain 45-50cc of gas, you can drain each into a container to measure OR use clear tube on drain nipple to determine height.

How many turns are the pilot screws set at?

Your rebuilder synched the throttle plates? (bench synch)
Have you discussed with him? His recommendations?

[roundhouse]

Originally Posted by ducatiman

2000RPM at full throttle?

is your cable freeplay allowing the throttle plates to fully close?

does the idle adjust knob have any effect? (turning down from your 2000RPM?
does the choke offer any aid to starting?

To confirm adequate fuel flow...each bowl should contain 45-50cc of gas, you can drain each into a container to measure OR use clear tube on drain nipple to determine height.

How many turns are the pilot screws set at?

Your rebuilder synched the throttle plates? (bench synch)
Have you discussed with him? His recommendations?

Idle screw has no effect

I pulled the bowls and I cannot be certain but it appeared to 7-8 teaspoons of fuel but I could be way off

pilot screws...........hum? What are these pilot screws you speak of?

carb was eye balled synced and I have made one of those sync contraptions our of bottles, stoppers and hose but I need it to idle on it's own before I attempt it.

so, pilot screws. what effect do they have? I will do some google work.

Thanks for your help!

[ducatiman]

i asked you 7 questions...you've answered just 3 or 4.

[jkv45]

Originally Posted by roundhouse

And it will only run about 2,000 RPM. Carb was just rebuilt by pro after I rebuilt it and it is no better than when I did it. Spark is fine. Compression is good (R 192 L 179). I do not think there are any vacuum leaks. Fuel is getting to carbs but I do not know how much.

Engine will rev up with a shot of starter fluid. So it is a fuel delivery prob?

I took the petcock apart and cleaned it out before trying any of this and it was in poor shape but is spotless and flows now. Could that diaphragm thingy have anything to do with it?

I just cannot for the life of me figure this out. Any leads would be much appreciated.

I am so close! dying to ride it!

I think that's the key right there.

Sounds like there is a problem with the assembly or adjustment of the carbs. If you paid someone to do it, you should contact them. If they are a "pro" they will help you sort it out and re-check the assembly and adjustments. A real pro will do whatever it takes to make it right.

[roundhouse]

Originally Posted by ducatiman

i asked you 7 questions...you've answered just 3 or 4.

well alrighty then.


2000RPM at full throttle? Yes

is your cable freeplay allowing the throttle plates to fully close? Yes

does the idle adjust knob have any effect? (turning down from your 2000RPM?
does the choke offer any aid to starting? No and No

[ducatiman]

Your rebuilder.....
have you discussed with him? His recommendations?

What methods did he use to clean? ultrasonic? sodablast?

I stand at the ready to give them a second look, if you choose. Apparently something remains seriously wrong.

[roundhouse]

Originally Posted by ducatiman

Your rebuilder.....
have you discussed with him? His recommendations?

What methods did he use to clean? ultrasonic? sodablast?

I stand at the ready to give them a second look, if you choose. Apparently something remains seriously wrong.

I do not know what he did. It was a buddy deal. the guy is a tech who owns a local lawn tractor sales and repair so I figured a small engine carb is a small engine carb.

Thanks, if I cannot get it going I may holler at ya. I assume I would ship the carbs?

[ducatiman]

"Thanks, if I cannot get it going I may holler at ya. I assume I would ship the carbs?"

correct, I routinely do this, USPS Priority (using their medium box) about $13 to ship.

I invite you to read some forum feedback from fellow members https://www.ninjette.org/forums/showthread.php?t=239678

[roundhouse]

I am going to take it apart and see if maybe there was trash in the line when I put it back on. If not I will definitely send it your way.