Sudden GT200 Problem
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Molto Verboso
Gina, 1965 Vespa 180SS, Bella,1968 Vespa 150 Super, (Both NZ new Airco assembled), Francesca, 2006 Vespa LX150, Sofia, 2007 Vespa GT200
Joined: 21 Jan 2015
Posts: 1241
Location: Hamilton, NZ
Fri Feb 08, 2019 11:55 pm quote
Yesterday (Fri) I was about to scoot off to work on Sofia when she decided that idling wasnít her cup of tea and refused to do so. She would start and I could keep her running with the throttle but she sounds distinctly chuffy and flat.
I thought she had blown the exhaust gasket so I was given the go ahead to take Francesca instead and I spent time today intending to change the gasket. However, on inspection it was clear that the problem lay elsewhere. I spoke to a local friend/guru who suggested HT problems, so I took the plug lead off and removed the coil and checked for continuity which is good across the coil and to the plug cap. I also pulled the plug out - oh for smaller hands - and it was wet so I dried it, tested for spark which was strong and consistent, and reassembled it all.
Started her again and no change.

Any ideas?
Molto Verboso
Kymco AK550
Joined: 09 Feb 2008
Posts: 1119
Location: UK
Sat Feb 09, 2019 12:12 am quote
On the assumption that you haven't changed anything recently is there any chance you have a vermin problem? Mice like to nest in air filters and its even possible for something to crawl into the silencer and block it. Well that's the imaginative idea anyway. Otherwise its all the usual things such as oily deposits in the air intake/throttle housing/air filter. Is it a fuel injected model or carb?
Ossessionato
Joined: 22 Oct 2011
Posts: 4045
Location: Tega Cay, SC
Sat Feb 09, 2019 6:30 am quote
maybe the auto choke has gone wonky. easy enough to check
Molto Verboso
Gina, 1965 Vespa 180SS, Bella,1968 Vespa 150 Super, (Both NZ new Airco assembled), Francesca, 2006 Vespa LX150, Sofia, 2007 Vespa GT200
Joined: 21 Jan 2015
Posts: 1241
Location: Hamilton, NZ
Sat Feb 09, 2019 8:36 pm quote
Roadster, the vermin problem in not unfeasible, it started okay and I rode it about 20m to the front gate and then it was reluctant to idle. Possible I guess.
Tierney, it has a relatively new choke, I had a really big service in May 2017 and have done 2000km since. I have started using her more regularly now I am retired as I have a part time role close to home.
I intend to talk to the local dealer tomorrow morning.
Molto Verboso
Kymco AK550
Joined: 09 Feb 2008
Posts: 1119
Location: UK
Sun Feb 10, 2019 12:40 am quote
So its a carb model with autochoke. Given that the plug was wet I suppose the choke is not releasing as quickly as it should. Check any electrical connection to it which may act as a heater to make it release more quickly. If present it would be a 12 volt feed which switches on with the ignition.
Hooked
2005 Vespa LX 150, 2005 GT 200
Joined: 13 Sep 2016
Posts: 286
Location: Hackettstown, New Jersey
Sun Feb 10, 2019 7:36 am quote
Check all your vacuum hoses for leaks. I was going crazy trying to figure out why my LX 150 stopped idling. Turned out to be a disintegrating vacuum hose. I replaced it and all was good again.
Member
GT
Joined: 21 Dec 2018
Posts: 18
Location: Delray Beach, Fl
Sun Feb 10, 2019 8:44 am quote
Bad gas possibly?
Molto Verboso
Gina, 1965 Vespa 180SS, Bella,1968 Vespa 150 Super, (Both NZ new Airco assembled), Francesca, 2006 Vespa LX150, Sofia, 2007 Vespa GT200
Joined: 21 Jan 2015
Posts: 1241
Location: Hamilton, NZ
Sun Feb 10, 2019 10:33 am quote
DelrayDad wrote:
Bad gas possibly?
Least likely of possible causes (though I'm not discounting it), it has a reasonably fresh tank and we use the same station for our cars and they aren't suffering.

Mopedlar, these were refreshed in the big service in 2017, but again, possible.
Molto Verboso
Gina, 1965 Vespa 180SS, Bella,1968 Vespa 150 Super, (Both NZ new Airco assembled), Francesca, 2006 Vespa LX150, Sofia, 2007 Vespa GT200
Joined: 21 Jan 2015
Posts: 1241
Location: Hamilton, NZ
Tue Feb 12, 2019 3:42 am quote
The Verdict.
So, Sofia is all fixed and running sweetly again after a visit to the local dealer. She is now lighter by virtue of the SAS being removed and deposited in the rubbish along with the dirty spark plug. While they were there they cleaned out the air box and even removed a few mls of the oil they put there nearly 2 years ago.
Firstly, I was blissfully unaware that we had the SAS on our scooters here in NZ, I thought that was almost exclusive to the States, and secondly, with the shorter runs things werenít getting quite hot enough on the way to and from work. Time to take the long way home.
The weather is looking promising tomorrow, I may need to check how well she is going. The guys in the shop reckon she goes as well as their 250 GTS.
As an aside, when I picked her up, the industrial unit next door had a small cabinet smoker going and they had done a full cabinet of albacore, or short finned tuna. That tasted amazing!
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