OP
@sleepy_samoyeds avatar
UTC

Lurker
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
 
Lurker
@sleepy_samoyeds avatar
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
UTC quote
Hi, I recently bought a 2008 Vespa LXV150. It was running okay but occasionally it would stall out and I'd have to pull in the shoulder and wait a little bit until I could accelerate again. I am currently cleaning the carburetor and am no mechanic but I am trying to learn.
I noticed while following this video:
at 51:10 my pump bellow is melted and when I push on the pump like in the video it does not compress and no carb cleaner sprays.
I tried to take it apart to see what is stuck but I cannot get the pin out.
I am unsure what I can do to fix this issue or if this is part of the reason why my bike is stalling out.

Thank you!
@juan_orhea avatar
UTC

Molto Verboso
S150 '09, Beo 500ie '08
Joined: UTC
Posts: 1280
Location: Bermuda
 
Molto Verboso
@juan_orhea avatar
S150 '09, Beo 500ie '08
Joined: UTC
Posts: 1280
Location: Bermuda
UTC quote
I understand the issue you're seeing is that the accelerator pump isn't activating - not sure what to tell you there - but that rubber bellows is a generic part for which you can find a replacement online for much less than Vespa channels will be selling it. My replacement came from eBay and was listed as a Harley part, P/N 27311-76. Six bucks including shipping, I think.

I am not certain that a sticking accelerator pump will cause the engine to stall. Others would know better than I, but my impression is that that extra spritz feature is for improved acceleration off the line. What I have seen on other scooters, though, is that a variator system that isn't operating smoothly can cause the CVT to get stuck in "high gear." This causes the engine to act very sluggishly, as if it were being starved of fuel, especially going uphill. In reality it is simply lugging.

Your situation could be caused by corrosion or schmutz on the bushing that the variator slides in and out on, causing the transmission to respond slowly when the variator is "in" (ie, in "high gear") but should be "out" (ie, in "low gear."). Once you stop, the clutch spring slowly prevails, and the variator returns to its designated "out" ("low gear") position.

The problem may be occurring as the transmission is gearing up too slowly too, but you wouldn't notice it.
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43934
Location: Pleasant Hill, CA
 
Moderaptor
@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43934
Location: Pleasant Hill, CA
UTC quote
With no accelerator pump, when you twist open the throttle the mixture into engine suddenly gets very lean, and can cause a stutter or a stall.

I'm not sure it can be mended (but I've never had to try to yet) - a new carb may be in your future.
OP
@sleepy_samoyeds avatar
UTC

Lurker
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
 
Lurker
@sleepy_samoyeds avatar
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
UTC quote
Juan_ORhea wrote:
I understand the issue you're seeing is that the accelerator pump isn't activating - not sure what to tell you there - but that rubber bellows is a generic part for which you can find a replacement online for much less than Vespa channels will be selling it. My replacement came from eBay and was listed as a Harley part, P/N 27311-76. Six bucks including shipping, I think.

I am not certain that a sticking accelerator pump will cause the engine to stall. Others would know better than I, but my impression is that that extra spritz feature is for improved acceleration off the line. What I have seen on other scooters, though, is that a variator system that isn't operating smoothly can cause the CVT to get stuck in "high gear." This causes the engine to act very sluggishly, as if it were being starved of fuel, especially going uphill. In reality it is simply lugging.

Your situation could be caused by corrosion or schmutz on the bushing that the variator slides in and out on, causing the transmission to respond slowly when the variator is "in" (ie, in "high gear") but should be "out" (ie, in "low gear."). Once you stop, the clutch spring slowly prevails, and the variator returns to its designated "out" ("low gear") position.

The problem may be occurring as the transmission is gearing up too slowly too, but you wouldn't notice it.
Thank you for the information! I'll have to get that replacement bellow
OP
@sleepy_samoyeds avatar
UTC

Lurker
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
 
Lurker
@sleepy_samoyeds avatar
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
UTC quote
jimc wrote:
With no accelerator pump, when you twist open the throttle the mixture into engine suddenly gets very lean, and can cause a stutter or a stall.

I'm not sure it can be mended (but I've never had to try to yet) - a new carb may be in your future.
Ohh okay, thank you. It does struggle when I need to accelerate quickly. Hoping not to need a new carb but will post if I find a solution!
@grunion avatar
UTC

Enthusiast
150LX
Joined: UTC
Posts: 74
Location: Sechelt BC
 
Enthusiast
@grunion avatar
150LX
Joined: UTC
Posts: 74
Location: Sechelt BC
UTC quote
I have not done this on mine yet but the accelerator pump is just a small piston. I would dismantle the carb and clean all the orifices and jets thoroughly, perhaps the inlet to your accelerator is just plugged? While you are in there, examine the seal on the plunger as well. This should all be serviceable. The bellows is just to keep carp out of the mechanism.
OP
@sleepy_samoyeds avatar
UTC

Lurker
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
 
Lurker
@sleepy_samoyeds avatar
2009 LXV 150
Joined: UTC
Posts: 4
Location: New Jersey
UTC quote
Got the mechanism out! Had to use vice grips to unscrew the spring. It was stuck from gunk in the screw hole. Jetted it with carb cleaner and the mechanism works well now.
@grunion avatar
UTC

Enthusiast
150LX
Joined: UTC
Posts: 74
Location: Sechelt BC
 
Enthusiast
@grunion avatar
150LX
Joined: UTC
Posts: 74
Location: Sechelt BC
UTC quote
Excellent happy ending.
How about posting a picture of your Sammy (somewhere?). We had a lovely Sammy for 14 years and we miss him a lot. Wonderful dogs.
UTC

Veni, Vidi, Posti
Joined: UTC
Posts: 7092
Location: Tega Cay, SC
 
Veni, Vidi, Posti
Joined: UTC
Posts: 7092
Location: Tega Cay, SC
UTC quote
Easiest (and probably the best way) to clean a carb is to dismantle it as far as possible and chuck everything into a sonic cleaner. If you don't have one, most shops that caters to dirt bikes will. For a small fee, they could take care of it for you especially if it's a bike shop you frequent or if you buy some supplies while you are there. After the soak, rinse everything with water, blow out all the openings with some air and let it dry. Pay particular attention to the rubber bits - gaskets, diaphragm and any of the little o-rings. Replace anything that looks wonky.
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