150cc will not stay running

[scootex]

I've replaced the carb and did the setting thing with the air mixture screw. It'll start, rev up to 2K and then die. If it does stay running, as soon as you bring the idle down it sputters and dies. I'm about to put a 45 slug into it and end it's existence.
No, I wouldn't do that. What could be the problem? Any suggestions would be helpful......

[yosemite]

Did you by any chance take the carb off to clean it and took the Diaphgram out? It sounds like the Needle and or Diapghram is not working and maybe sticking or stuck not allowing the needle to rise. Or maybe when you cleaned it the Needle Guide fell out and is not in there.
Sam

[scootex]

Sam, it was a new carb I installed. I did take the top off to make sure the diaphram was good and seated properly. I haven't taken the needle valves out. Do you think I should to clean them and check for grit. Can I spray carb cleaner in the hole or would that hurt it? I just can't believe something so simple can as this machine can be so hard to troubleshoot and fix.

[yosemite]

New carb you should not need to clean anything.

Q1. Did you pull the diaphgram out and spring and then put it back in or did you just take the CAP off to look at the diaphgram.
Q2. Did you put the spring back in right? On the underside of the CAP is a round extruding piece that the SPRING fits OVER.
Q3. Did you turn any screws on the CARB,
Q4. Did you take the CARB BOWL OFF etc..
Q5. Why did you get a new carb and is it the same size as the old one.
Q6. What else did you buy and put on or take off
Q7. DID YOU PLUG the ENRICHER back into the harness.

Carbs are pretty simple to fix but need details of what you did or did not do.

Also can you put up pictures of the CARB are and hoses we might see something wrong.
Sam

[scootex]

A1-I took the cap off to make sure the diaphram was good and the little tab was in the right spot.
A2- I made sure to put the spring on the protrution and closed it up.
A3- Other than turn the mioxture screw all the way down, then 21/2 turns out.
A4- No
A5- It was bought by a mech that was trying to fix it an never put on. I finally went and retrieved it.
A6- Nothing.
A7- Yes.
I wish I could put pictures on here, but being 71 my computer skills are right up there with my scooter mechanic skills.

[scootex]

Do you have a phone number that I could call you and talk instead of doing this?

[skuttadawg]

Same size carb and jets ? Any leaks in the intake ? Drained out the gas and tried fresh gas ? Replaced the fuel filter ? Check the float valve as it may need to be bent a hair

[yosemite]

Check your PETCOCK it should be hooked up like this:
You may need to check for fuel flow from the tank to the carb.

If you have a different steup let me know.
If you have similiar to this I can tell you how to check for fuel flow.

Sam

["Big Guy"]

Sounds like your valves are closed up Scootex. I would start there -- it never hurts to check the valves and it only takes a few minutes to do.


-Rich

[scootex]

Well Big Guy, I watched your video on carb cleaning. I'm going to take mine and check the float pin and clean the other parts. I'll let you know how it turns out.

[scootex]

So Big Guy, I watched your video twice and then went and cleaned my new carb. Everything was as you showed. Of course being new, it was fairly clean. The float valve was loose and I sprayed all passages. Put it back together and installed on scooter.
It started right up but ran rough. When I gave it gas it bogged and backfired out the carb. Other than change my sparkplug I'm at a loss.
Could it be my valves and how hard are they to set? I'm getting very frustrated with the whole thing.

["Big Guy"]

Yeah, my first suggestion was a valve adjustment. If you like videos, this is a good start, and if you prefer written directions, you can try this link.

It's much easier when you do it in person. It only takes a few minutes to do without all the instruction babble. Like, my carb video is 24 minutes I think, but it takes me about 5 to actually do it.


-Rich

[scootex]

Thanks Rich, I'll try that tomorrow. I've had enough for today. I'll let you know.....Gene

[woowilly]

failing coil or CDI maybe.
I had a coil go bad once, wouldn't start with starter, then battery got low, started with kicker,
then no start with either once home.
CDI died a week later. might have been caused by the bad coil or a previously disconnected engine ground.
( bought non-running, easy fix resulted in a hard to start and poor running scooter.)
#38 idle and #112.5 main jets fixed the hard to start, die or carb backfire on rapid throttle open, and lean surgeing problems.

another time mine developed misfire when I hit 20mph, ran fine on stand.
turned out sparkplug wire core didn't quite go to the end of the wire.
fixed by cutting off 3/4 inch and reinstalled plug cap.
intermittantly same problem a few weeks later.
spring clip in sparkplug cap fell out when I pulled the cap off.

you could have a fuel flow restriction problem.
to test unplug and the plug rubber fuel line to carb, stick a siphon hose in tank,
start siphoning gas, temporarly stop gas flow with finger, plug hose into carb.
( safer to use a temporary hose and gas tank held higher than carb. )

could explain the symtoms, by the time you get to 2k rpm, no gas left in float bowl, so it dies.
If you manage to keep it running on what little is comming in, gas level in float bowl gets low, then when you go to idle, intake vaccum drops to low to pull enough gas out of the half empty float bowl.

[scootex]

Well guys, all my problems are gone. After taking the carb apart, replacing a few vacuum lines( that looked good) and replacing the sparkplug with a NGK CR7HSA it started up. I set the mixture and the idle and it's all good. Thanks for all the help, I appreciate it....Scooter on

[scootnwinn]

Nice now ride that thing. Keep the shiny side up