scooter idles fine but dies when i give it gas By kj (Read 3,214 times)

[kj]

I bought a 2009 Tomos Velo 150cc that sat for a long time. It only has 200 miles on it so everything is new. I managed to get it running but it will only idle and dies instantly if i touch the throttle.

what I have done:

changed fuel
new fuel filter
new spark plug
cleaned carb twice
checked all lines gas and vaccum(good)
new battery
checked airbox/ filter (good)
added seafoam to gas

The new spark plug has got some black on it after idling for 3 minutes which leads me to believe my mixture is rich since the throttle instantly kills the engine. The idle screw barely effects the idle speed and the a/f screw has no effect at all. I do not have air leaks. When i disconnect the vaccum hose from the t connector the engine idles higher/ better, but the throttle still kills it. What is my next step?

[Alleyoop]

If the the Fuel Ratio Mixture screw has no effect then the PILOT jet and or its PASSAGE are clogged.
Get a can of Carb Cleaner they come with a thin long straw. Take the PILOT JET out and make sure you can see light through it. Then with the JET still out stick the Thin straw into where the Pilot Jet screws into and spray.
Now Spray should come out from the tiny fuel outlets by the butterfly:

Once it starts to get fuel from the pilot jet You should be able to Kill the motor turning the Fuel Ratio Screw Clockwise. Then turn it out 2 turns since you say at idle the plug is black and start it up.

Then FOLLOW this procedure to adjust the mixture:
scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

Alleyoop



Spray should come out of the tiny fuel outlets when spraying into the PILOT JETs passage:



Spray should com out of the needle guide when spraying into the MAIN JET:

[mike6736]

That cave dud got a picture of everything! He do know his carbs...

Magoo

[Alleyoop]

Here is a step by step on how to adjust your carb:
Alleyoop

scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

[Deleted]

If it still won't run, check the airbox, snorkel and intake for cracks and leaks. I had the same issue with both 150's and both times the large end of the snorkel had slipped off the bottom of the air box.

[kj]

wow thanks for all of the help! Some great suggestions here but none fixed my scoot.

So i checked the carb again and i am 100% certain it is 100% clean. I followed the tuning tips and the a/f screw started to show signs of being effective but still not much difference. I checked the enricher/electric choke and it also is functioning properly. I double checked the air box and it is fine with a clean filter.

Is it possible that it is jetted in correctly?

I have a 112 main and 35 pilot (sea level blocks from beach). The reason i ask this is because while checking for leaks I decided to spray carb cleaner into the box while running the engine. This killed the engine just as if I had turned the throttle. Also my plug is brand new and turning black after less than 20 mins total of idling. Also if i disconnect the vacuum hose that runs from the carb to the "T" connector the engine revs higher (still dies with throttle here).

I have not attempted to adjust the vales b/c there is only 201 miles on it. Could this be my issue?

[kz1000st]

It never hurts to check the valves. It could be something dumb like low compression isn't raising the carb slide.

[kj]

so the valves are fine. today i tried a couple things and the scooter runs exactly the same whether the airbox is connected to the carb or removed from the carb altogether. the only thing that makes it rev higher is when i pull the vacuum hose that connects to the diaphragm on the top of the carb. which means i am need of less O2, right? however the brand new plug is black and slightly wet. its still dying every time the throttle is touched

[Deleted]

A cracked float or bad needle valve perhaps.

[Alleyoop]

Well if the plug is black and wet it is either miss firing or to much fuel. Check the Vacuum line going to the petcock and see if it is wet from fuel. It could be sucking in fuel from some other place but the carb.
Alleyoop

[kj]

Uh oh. I think the wet black plug is oil. This would explain why it is only strong enough to idle, right? What is a common problem that results from sitting too long that could be causing that? seals?