Battoo

Hi Guys or Girls

My wife and i have a 125cc scooter that when not running, empty's the carb of fuel and dumps it in the engine where the oil is, the oil is being changed regularly because of this ie twice a month.

most times we try to start the scooter it hydrolics / locks up and wont start on electric or kick.

i have adjusted the float level in the carb's fuel chamber but it still has the problem.

we only use the scooter, on average, three times a week so not used very often.

i thought the diaphram carbs were air tight so im stumped as to how the engine can syphon the carb.

any help is greatfully received

The scooter is a Moto-Zeta Rally sc

kind regards
les

hands without shadows

It sounds like your carb float is/was stuck open, but fuel could still not enter the combustion chamber this way unless an intake valve was also open. I would pull the valve cover and make sure the intake valve (s) are closing.

Don't try to crank it when its hydrolocked. Its easy to bend a con rod and thats not a cheap fix.

Until you get the problem fixed:
When your done using it, set the petcock to off and let the engine idle until it shuts off by itself. This will stop any fuel from reaching the engine untill you reset the petcock.

hands without shadows

Are you sure it is gas and not coolant?

Battoo

Hi thanks for your response

I assume a petcock is a fuel stop tap and if so the scooter doesn't have one, although i have considered retro fitting one. the problem with this is, when the float chamber is empty, it takes a while to start as the fuel pump is located just under the tank and works on suck/stop, blow/flow action via three pipes. these pipes are located into either side of the carb and into the intake manifold. this makes the bike take a while to fill up the chamber and ultimately flattens the battery.

I am sure it is petrol as the engine is air cooled and the fuel is being used even though the bike is not. There is no spillage onto the floor either.

regards

Jailbird1818

My Feedback: (5)

It's also possible the needle valve or seat needs replacing. The seat is usualy just an o-ring. It could be cracked or torn. They both should be in a carb rebuild kit.

-JB

DaveG55

That's pretty much what I was thinking.

Battoo

Hi thanks all,
i have now found the problem.

the fuel pump was leaking petrol into the pump vacuum pipe and was flowing straight into the manifold and into the engine.

the problem starting was flooding and not lack of fuel in carb, as originally thought.
again thanks for your reply's.

kind regards

les

DaveG55

That little motor has a fuel pump? I would have thought it was gravity fed. Or do you mean the diaphragm in the carb?

SLAYERDUDE

My guess is a pulse fed diphragm that works off crankcase pressure???

Battoo

hi,
yes its one of those and its bust. the pipe that uses the pressure to open the valve / pump / diaphram was draining the fuel from tank straight into manifold, where it gets the pressure pulse, and into the combustion chamber. then past the piston and rings into the oil.
a new valve should do the trick. I took the valve to bits and the diaphram had a tiny split. it was a sealed unit so a new one is needed.

regards

SLAYERDUDE

I'd get a full carb rebuild kit that should include the diaphragm.
Also take care to remove all parts from the carb and spray it down with carb cleaner then blow thru all passages with compressed air.
If your going to take it apart anyways might as well go thru the whole 9 yards and make it run like new.
Just be sure to count the turns in on the needles before removing them and write those #'s down.
(Just lightly seat the needles, they are easily damaged.)