Why is my S3 such a nightmare to start?

[mick1]

Iv'e uprated the main jet and pilot jet and changed the atomizer.
Not sure about the choke jet, is that different?

Yes....whip your choke jet out and you should see the numbers, not sure what you should be on but 50+ would be a starting point.

[nelson pk]

Twice you have said that as soon as you turn the choke off it dies, Is this correct?
If so, its not your choke jet. From what i can see reading through the posts, the initial advice from Darrell would be the way to go. If when you get it started you have to keep it running with the choke on, it is going to be lack of fuel through your pilot system (blocked pilot jet or pilot system in carb body) or some sort of major air leak.
If you have a large air leak, it wont start easily and wont run without lots of extra fuel.

[muffster]

Hello again gents.
A quick update. I got it running on friday eventually and it ran up and down the road fine.(apart from not finding 4th gear, bloody scooter!!) Turned off, return a few hours later kicks up no problem. Next morning again, kicks up and runs no problem, and now it's running fine after i knock the choke off when previously it died.
So now the choke is not an issue as it was before, why, no idea, i'm not doing anything differently!
So if i've got an air leak, where should i start. I have previously had it running and sprayed everywhere with carb cleaner to try and indicate any leaks but nothing.
At the moment it's got a 48 pilot, 130 main and a 50 choke jet.
Running a ScootRs exhaust with the air scoop off.
Do the choke jets come larger than a 50?
I'm hoping this might be an easy fix.

Thanks for your input.

[WINTERMODEL150]

Hello again gents.
A quick update. I got it running on friday eventually and it ran up and down the road fine.(apart from not finding 4th gear, bloody scooter!!) Turned off, return a few hours later kicks up no problem. Next morning again, kicks up and runs no problem, and now it's running fine after i knock the choke off when previously it died.
So now the choke is not an issue as it was before, why, no idea, i'm not doing anything differently!
So if i've got an air leak, where should i start. I have previously had it running and sprayed everywhere with carb cleaner to try and indicate any leaks but nothing.
At the moment it's got a 48 pilot, 130 main and a 50 choke jet.
Running a ScootRs exhaust with the air scoop off.
Do the choke jets come larger than a 50?
I'm hoping this might be an easy fix.

Thanks for your input.

Hi,this is what I do to check for air leaks





Blank off the inlet and fit the spark plug,i then made a blanking plate for the exhaust flange drilled the centre and fitted a rubber car valve and removed the centre so that air can then be pressurised up through the centre via a radiator pump.

Put the motor to bdc.

The motor is then pressurised to 1 bar for a period of 5 mins,if the engines sealed up nicely then you will see no drop in pressure,if the pressure drops then spray some soapy water around the engine to see where its leaking from easy

[muffster]

That's a great set up you have there mate. Simple but genius.
Well i've change the pilot jet from a 48 to a 50 and............ it starts first kick. So far, every time.
Wierd :wtf: Was that all it needed all this time?
I hope this has cured it at long last!