Low power at startup.
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Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Sat Jan 11, 2020 8:36 pm quote
Hi Guys,

Recently purchased a used a 2007 Vespa LX 50 with 2,500 miles. I had the carburetor cleaned, changed the fuel & vacuum lines and new batter. From a cold startup, the may turn off on first initial throttle and afterwards on the first couple of seconds, it struggles with power but after itís warmed up the issues go away. Could it be the carburetor jet dirty or a spark plug? Any help is appreciated!!!

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Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Sat Jan 11, 2020 8:37 pm quote
darwinsm81 wrote:
Hi Guys,

Recently purchased a used a 2007 Vespa LX 50 with 2,500 miles. I had the carburetor cleaned, changed the fuel & vacuum lines and new batter. From a cold startup, the may turn off on first initial throttle and afterwards on the first couple of seconds, it struggles with power but after itís warmed up the issues go away. Could it be the carburetor jet dirty or a spark plug? Any help is appreciated!!!


72438D88-99FD-4293-861E-B926728B9876.jpeg

Hooked
GTS 250
Joined: 26 Apr 2008
Posts: 264
Location: California
Mon Jan 13, 2020 4:19 pm quote
I don't have any experience with the LX, but this sounds like a choke issue to me.
Addicted
2006 LX150 (carbed) | 2007 GT200
Joined: 29 Jun 2016
Posts: 926
Location: Toronto
Mon Jan 13, 2020 4:53 pm quote
How long are you letting it warm up before you give throttle? This time of year (freezing temps), my LX carbureted needs a couple min warm up before she's willing to go anywhere. If I try before then, it's bogging and / or stalling.
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Mon Jan 13, 2020 5:19 pm quote
berto wrote:
How long are you letting it warm up before you give throttle? This time of year (freezing temps), my LX carbureted needs a couple min warm up before she's willing to go anywhere. If I try before then, it's bogging and / or stalling.
Thanks for the reply, I just got the moped so certain things are new to me. I would startup the moped and hit the throttle right away and it would die. So I would try again but this time, I would hit the throttle several times rapidly and it turns on but struggles with speed - 1 minute into ride. After riding for a couple of minutes, the problem does go away and am able to turn it off and on again with no issues - 10-15 minutes in. The only thing i do notice is that the light of the panels light goes a bit down but not to the point that the moped shuts off on me. Tonight, I am going to change the spark plug as it seems the previous owner did not kept service the moped properly and rather just to change the part.
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Mon Jan 13, 2020 5:22 pm quote
AnnDee4444 wrote:
I don't have any experience with the LX, but this sounds like a choke issue to me.
I am going to let it warm up before throttling and see if i get the issue. I am hoping its not the choke. Thanks!
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Thu Jan 16, 2020 8:35 pm quote
berto wrote:
How long are you letting it warm up before you give throttle? This time of year (freezing temps), my LX carbureted needs a couple min warm up before she's willing to go anywhere. If I try before then, it's bogging and / or stalling.
Just an update, i changed the spark plug and changed the oil which looked like thick chocolate! It definitely runs with less vibrations but as I stated before, still low power from a cold start but 5 minutes into the ride itís normal. Do you usually warm it up for several minutes before going on the ride? [img][/img]

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Ossessionato
73 Rally, 74 Rally, 76 ET3, 80 P200, 06 PX150, 65 Li225 Silver Special, 86,95,96 Elite 80s, 2015 HD Road Glide Special, 2011 Ural Tourist
Joined: 18 Jan 2012
Posts: 3616
Location: Oceanside/ SF
Thu Jan 16, 2020 11:53 pm quote
Sounds like a valve adjustment is needed. Usually the exhaust valve gets out of spec first. If it never got better Iíd say carb but the fact that it runs better and restarts easier once warm would make me lean towards valves.
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Sat Jan 18, 2020 2:57 am quote
MJRally wrote:
Sounds like a valve adjustment is needed. Usually the exhaust valve gets out of spec first. If it never got better Iíd say carb but the fact that it runs better and restarts easier once warm would make me lean towards valves.
Hereís a video of what usually happens - at 58 seconds in is the issue that I am having. Within the first couple of minutes, the idling would not be consistent at a stop. Sometimes it would go low enough that it would shut off. Carb is clean, new oil, spark plug, fuel and air lines. The fuel tap work and I dont think itís a air leak as am able to go normal. I havenít checked the secondary filter and itís been cold weather for the past weeks but Iíve been riding it every day. Someone had mentioned the choke cable could be the culprit.
[url]
Ossessionato
73 Rally, 74 Rally, 76 ET3, 80 P200, 06 PX150, 65 Li225 Silver Special, 86,95,96 Elite 80s, 2015 HD Road Glide Special, 2011 Ural Tourist
Joined: 18 Jan 2012
Posts: 3616
Location: Oceanside/ SF
Sat Jan 18, 2020 6:15 am quote
darwinsm81 wrote:
MJRally wrote:
Sounds like a valve adjustment is needed. Usually the exhaust valve gets out of spec first. If it never got better Iíd say carb but the fact that it runs better and restarts easier once warm would make me lean towards valves.
Hereís a video of what usually happens - at 58 seconds in is the issue that I am having. Within the first couple of minutes, the idling would not be consistent at a stop. Sometimes it would go low enough that it would shut off. Carb is clean, new oil, spark plug, fuel and air lines. The fuel tap work and I dont think itís a air leak as am able to go normal. I havenít checked the secondary filter and itís been cold weather for the past weeks but Iíve been riding it every day. Someone had mentioned the choke cable could be the culprit.
[url]
A few questions- When you start it do you really have to play with the throttle to get it to start or just a few spins and it starts? If you really have to twist the throttle and crank it over for more than five seconds Iíd say valves. If it starts the same as the summer but lacks performance till itís warm Iíd say carb now. I would not say secondary air system, evap system etc. If those were affected it would run shitty all the time.

Ok how cold are we talking about here? A few years back someone on here posted similar cold running questions. He owns a LX150 in NYC. He was commuting to work in the really low temps and had poor performance until things warmed up. Same carb in the summer has no problem whatsoever. I chalked it down to it being too cold outside/old rubber diaphragm being affected by the temps. We ran out of time before we could test my hypothesis and now his scooters in his living (Iíll text him and see if he can experiment.)

Item #3- you donít have a choke cable. You donít even have a choke. What you do have is an auto enricher/bystarter. If youíd believe it when cold, the carb has a passage in it that gives more fuel than needed. As the auto enricher gets voltage it warms up and a needle in it extends out, which plugs that extra fuel passage. Thatís all done internally and on a normal scoot takes just under a minute to extend. You can actually hear your idle slow down after a short period which is proof the needle has plugged the extra fuel circuit. If yours is broken itíd be getting too much fuel all the time and performance would suffer all across the board. You can test the auto bystarter by removing it from the carb, measuring the needle length with a cold engine, giving the bystarter voltage and then re measuring after a few minutes. Iím sure thereís a YouTube video showing that test somewhere.

See if you can time how many seconds it takes the get the scooter started to narrow down valves vs carb and if you can note the outside temps. Thanks
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Sat Jan 18, 2020 2:06 pm quote
MJRally wrote:
darwinsm81 wrote:
MJRally wrote:
Sounds like a valve adjustment is needed. Usually the exhaust valve gets out of spec first. If it never got better Iíd say carb but the fact that it runs better and restarts easier once warm would make me lean towards valves.
Hereís a video of what usually happens - at 58 seconds in is the issue that I am having. Within the first couple of minutes, the idling would not be consistent at a stop. Sometimes it would go low enough that it would shut off. Carb is clean, new oil, spark plug, fuel and air lines. The fuel tap work and I dont think itís a air leak as am able to go normal. I havenít checked the secondary filter and itís been cold weather for the past weeks but Iíve been riding it every day. Someone had mentioned the choke cable could be the culprit.
[url]
A few questions- When you start it do you really have to play with the throttle to get it to start or just a few spins and it starts? If you really have to twist the throttle and crank it over for more than five seconds Iíd say valves. If it starts the same as the summer but lacks performance till itís warm Iíd say carb now. I would not say secondary air system, evap system etc. If those were affected it would run shitty all the time.

Ok how cold are we talking about here? A few years back someone on here posted similar cold running questions. He owns a LX150 in NYC. He was commuting to work in the really low temps and had poor performance until things warmed up. Same carb in the summer has no problem whatsoever. I chalked it down to it being too cold outside/old rubber diaphragm being affected by the temps. We ran out of time before we could test my hypothesis and now his scooters in his living (Iíll text him and see if he can experiment.)

Item #3- you donít have a choke cable. You donít even have a choke. What you do have is an auto enricher/bystarter. If youíd believe it when cold, the carb has a passage in it that gives more fuel than needed. As the auto enricher gets voltage it warms up and a needle in it extends out, which plugs that extra fuel passage. Thatís all done internally and on a normal scoot takes just under a minute to extend. You can actually hear your idle slow down after a short period which is proof the needle has plugged the extra fuel circuit. If yours is broken itíd be getting too much fuel all the time and performance would suffer all across the board. You can test the auto bystarter by removing it from the carb, measuring the needle length with a cold engine, giving the bystarter voltage and then re measuring after a few minutes. Iím sure thereís a YouTube video showing that test somewhere.

See if you can time how many seconds it takes the get the scooter started to narrow down valves vs carb and if you can note the outside temps. Thanks
Thatís the thing that I have a hard time understanding. To turn on thereís no issues at all. Click the turn on button and it starts right up and much better after all the changes (it does have a choke cable). As i stated previously on hitting the throttle, There isnít enough power so it moves around 10-15 tops. After a couple of minutes the power does pick up to normal but on idle that happens. When I got the Vespas carved checked/cleaned, it was warmer temps, around 40 degrees which either I didnít notice it or it didnít happen. Now the temp is around 30 degree I started seeing this issue. Now at 20 degrees the issues maintain and noticed a bit of speed drop off on top speed by a couple of miles.

The white part on the right is the choke cable.
[/img]

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Ossessionato
73 Rally, 74 Rally, 76 ET3, 80 P200, 06 PX150, 65 Li225 Silver Special, 86,95,96 Elite 80s, 2015 HD Road Glide Special, 2011 Ural Tourist
Joined: 18 Jan 2012
Posts: 3616
Location: Oceanside/ SF
Sat Jan 18, 2020 5:41 pm quote
The guy who was having the problem years ago is in Brooklyn, not the city. Anyways I reached out to him and havent heard anything back. I'll see if he can corroborate the cold temperature theory.

For the sake of this being a public forum can you do a science experiment and note what conditions the motor is running like shit in? Temps, what were the results of your ride? See if we can develop a trend? Hopefully you get a warm spell and can see if it comes and go with the temps as it cools down.

The white thing is the enricher/ choke cable/ whatever you want to call it. Its supposed to have a black plastic weather cover over it. The two wires coming out of it are what plug into the harness and what makes it do its thing.

https://sip-scootershop.com/en/products/cover+echoke+piaggio+_pi828844

Another question, what condition is that hose at the bottom right of the screen? That should be soft. That is the vacuum line that opens your fuel tap. If its hard or brittle the tap wont have the necessary vacuum and it will cause fuel starvation issues. There was a lady on here who used to remind folks every two years to change theirs out (Judy RIP). If those havent been swapped lately you might want to before it strands you.
Member
LX 50
Joined: 07 Jan 2020
Posts: 13
Location: Queens
Sat Jan 18, 2020 8:02 pm quote
MJRally wrote:
The guy who was having the problem years ago is in Brooklyn, not the city. Anyways I reached out to him and havent heard anything back. I'll see if he can corroborate the cold temperature theory.

For the sake of this being a public forum can you do a science experiment and note what conditions the motor is running like shit in? Temps, what were the results of your ride? See if we can develop a trend? Hopefully you get a warm spell and can see if it comes and go with the temps as it cools down.

The white thing is the enricher/ choke cable/ whatever you want to call it. Its supposed to have a black plastic weather cover over it. The two wires coming out of it are what plug into the harness and what makes it do its thing.

https://sip-scootershop.com/en/products/cover+echoke+piaggio+_pi828844

Another question, what condition is that hose at the bottom right of the screen? That should be soft. That is the vacuum line that opens your fuel tap. If its hard or brittle the tap wont have the necessary vacuum and it will cause fuel starvation issues. There was a lady on here who used to remind folks every two years to change theirs out (Judy RIP). If those havent been swapped lately you might want to before it strands you.
MJRally, that photo was before I changed the both lines. ill try to keep a diary down on the rides. Weíll have some irregular temps next week but this issue has definitely aligned itself with the cold temps. When I got the carb clean, the temperatures was around 45-50 and no issues or least no noticeable. 30ís the idling was showing the signs on the video and now that the temps were in the high teens, worst idling issue and now some loss of power top speed. Maybe the choke cable is not working correctly.
Enthusiast
2008 Vespa LX 50, 1964 Vespa 150 VBB
Joined: 03 May 2013
Posts: 96
Location: Brooklyn, NY
Sun Jan 19, 2020 7:04 am quote
new carb is $30 on ebay
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