Poor starting on Mugello 225 with 30mm Dellorto

[CHRIS in MARGATE]

Poor starting on Mugello 225 with 30mm Dellorto PHBH solid mount.
Not often I have to ask but after a day I am no further resolving this problem for a Club Member.
Guy has never ever needed to use choke to start since he bought this scooter 6 months ago. It goes very very well. Recently been a complete pig to start.
Today I drained the tank and refilled with quality petrol and oil.
Changed spark plug.
All electronic stator resistance values in range.
Stripped carb and cleaned.
AV266, 118 Main, 55 Pilot, 60 Starter, 2nd clip down of 4 on needle, Open mouth.
Polished choke plunger and fitted new choke adjuster to ensure that choke operates freely.
Changed float needle.
Floats do float.
Tweaked float adjustment to ensure slightly earlier cut off.

Scooter will not start unless "Easy Start" sprayed through venturi.
Once started pretty smokey and choke makes little difference. Had a 5 mile test run...not bad and lots of power. Scooter restarts when warm.
Will not restart when cold.
Exhaust plugged with glove whilst smoking and engine struggled and died so "probably" not oil seal.

Anybody been here before; feeling a tad useless and don't know where to go next.

[MickYork]

Stuck ring ?

Gunged up rings/top end

[CHRIS in MARGATE]

My very thoughts but was hoping for an easier fix.

[Rich Oswald]

It's easy to blame carburation but it's in the ball park so should start whatever. My first thought was stuck rings, what's the compression like? Are there definitely no kinks in the fuel pipe, elementary I know but I have done it! Have you ruled out the CDI and HT lead?

Probably nothing to do with starting but if it has started without choke then it is probably too rich on pilot / slide which won't help. I run a 30mm on Muggy 225 and wasn't great on 55 pilot so dropped it to 52 and it's spot on. you need to be looking for something that has changed or failed, sorry for stating the obvious,

Rich'

[CHRIS in MARGATE]

All sound advice and yes tried all except CDI which I will try tomorrow. I'm quite OCD with everything fitted to Lambrettas; I like everything spot on so all doubt is eliminated. It has to be 100%; "that'll do" just doesn't do it for mem
I was explaining same thing to owner : nothing touched, tinkered with, altered or replaced so something has recently deteriorated or failed. That's why I drained and replaced the fuel as it's the only thing that may have altered.
Interesting about the 52 pilot; the mixture screw has little effect on the 55.
CDI and then top end strip.

[St George]

Hi Chris, how are you mate.
If it has been running that rich for so long, I would suggest a build up of wet carbon in the combustion chamber ( bit like a sooted up chimney ), this can have the same symptoms. This can absorb the incoming fuel. Worth a quick strip-down and polish of the surfaces.

Regards Colin

[coaster]

One thing that has changed recently in the UK is the air temperature is a good bit lower which will have an effect on carburation.

That said, my money is also on a ring related issue as well