Starting issues

[Jono]

I have a GP150 (Indian origin) that was rebuilt some time ago in standard format.
Upon starting from cold ( choke on) the engine fires and starts on third kick. However, if throttle opened engine cuts out, only way to overcome is to keep bleeping throttle until revs increase and then is ok. Once overcome engine runs
sweet with no issues.Carb is a Jetex with 42mm Clubman exhaust.
Any ideas where to start looking to resolve issue would be appreciated.
Jono

[CHRIS in MARGATE]

Filter in the fuel banjo.
Choke lifting up sufficiently.
Raise pilot in carb to a 50
Decrease plug gap
Air filter bellows seated tightly

Try those for starters.

[HxPaul]

Once running from cold you should not touch your throttle,but should let the engine warm up before turning the choke off.

[Jono]

Thanks Chris and Paul will give all items a try/ check.
Memory is a strange thing but I remember as a lad going to work starting my scooter with choke and riding straight off not warming up engine before opening throttle. Equally, my other GP works/ rides from cold on choke and within 100yrds choke off. This scooter can not be ridden until revs are increased progressively by throttle blipping. Once overcome engine ticks over fine with no choke.
Let’s see what happens when checked out as Chris suggests.
Jono

[hullygully]

ditto let the poor be-ich warm up

[Fast n Furious]

Has it got the right sized choke jet?

[Jono]

Hi Fast n Furious
The engine is a bog standard Indian 150 with a Jetex Carb.
Will take Carb off and check jets etc, any idea what jet sizes would be a reasonable starting point as reference.
I have to say sometimes when having been running for a time and then left standing for half an hour or so it does not start
easily and can result in plug having to be changes due to flooding.
Not the most reliable animal
Jono

[CHRIS in MARGATE]

You need a compression test. Rings may well be worn.

[CHRIS in MARGATE]

You should have 118 Main; 50 Choke and 45 Pilot. On a jetex I would use a 48 or a 50.

2 things to inspect:
Float needle valve. Must be a red tip. Attach pipe to inlet and blow through whilst lifting float to make sure it shuts off.
Float spindle sticking in float. Remove and run a drill bit by hand through. Very common fault on Jetex with modern petrol.

[Jono]

Thanks all, looks like I have a few hours in garage this wet and windy weekend to follow up all possible issues identified.
Once again many thanks for suggestions, much appreciated.
Jono

[CHRIS in MARGATE]

Any luck?