Fri Jul 09, 2021 10:38 am

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Fri Jul 09, 2021 10:38 am linkquote
I know the topic of removing the EVAP has been beaten to death, so.. apologies, but I just want some validation that my current situation is indicative of a clogged EVAP.

First I will say, that the hose (C on image) on the evap system coming from the carb to the tee junction as seen in the image, is broken near the tee junction. so for all intends and purposes I have the hose removed from the carb currently, which I know is not the complete evap removal, but seems to be the test they suggest to see if problems are evap related.

As for the image, my evap system is difference, where I have two hose nipples on the manifold just like in https://modernvespa.com/forum/topic65874 <--this write up

So basically what is happening, it struggles and stalls at red light, especially when it was hot. and at high speeds and accelerating it struggles, feels like someone is pulling a rope on me like the rpm flutters if that makes sense.

I am not oppose to removing the evap even though I don't understand fully the repercussions? Will it just make Leonardo Dicaprio upset? does the rollover valve save my fuel in an accident? I think the only thing I am concerned with is fuel emitting from it while parked, I park some places where vapours and leaks would not be appreciated.

And again, I am having these symptoms but are they are indicative of evap? considering I already have a broken 'C' line? my carb was cleaned a year or two ago (didnt need it)... so I somewhat can rule that out I guess...



Fri Jul 09, 2021 11:30 am

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
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Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11843
Location: The state of insanity, SoCal
Fri Jul 09, 2021 11:30 am linkquote
Pull #3 and just tuck it in somewhere. No biggie. Don’t touch anything else…

*unless* you’ve got a cracked intake manifold OR one of the two coming off the intake is compromised.

The small one, you can trace it back, is vacuum for the fuel tap. Check it and your intake throughly for any kind of deterioration.

The big one is bullshit. You can pull it and cap it off, but if it looks fine don’t mess with it. It goes to a one way valve so no biggie there.

If you wind up replacing the intake, eliminate and cap it. And if you do the intake, do the fuel and vacuum lines.

hth
Fri Jul 09, 2021 12:46 pm

Addicted
2009 LX 150, 2008 GTS 250
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Location: Birmingham, Alabama, USA
 
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Posts: 857
Location: Birmingham, Alabama, USA
Fri Jul 09, 2021 12:46 pm linkquote
You might spray some carburetor cleaner on your rubber intake manifold and those two vacuum hoses to check them for leaks. At idle if you have a vacuum leak there, the spray will raise the idle speed momentarily. As Greasy said, basically you have the correct hose already unhooked. Where your tee is broken.
Fri Jul 09, 2021 1:07 pm

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Location: Canada
 
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Fri Jul 09, 2021 1:07 pm linkquote
Should I just leave it broken? or seal the tee and keep the carb open? and basically spray the two nipples with carb cleaner and if rises then fix them?

I meant to add sometimes when i open gas cap it hisses, and the problems are more noticeable when im low on gas (maybe coincidence)
Fri Jul 09, 2021 1:17 pm

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11843
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11843
Location: The state of insanity, SoCal
Fri Jul 09, 2021 1:17 pm linkquote
Remove c entirely. It does nothing.

Ride and report.

But if I had to guess, you’ve got a vacuum leak somewhere.
Fri Jul 09, 2021 1:26 pm

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Fri Jul 09, 2021 1:26 pm linkquote
And cap the tee end of c?
Fri Jul 09, 2021 1:29 pm

Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11843
Location: The state of insanity, SoCal
 
Sergeant at Arms
Weird 80's Vespas & Cool Vintage Lambrettas
Joined: 21 Oct 2005
Posts: 11843
Location: The state of insanity, SoCal
Fri Jul 09, 2021 1:29 pm linkquote
jezibel_tires wrote:
And cap the tee end of c?
Don’t know what you’re talking about. Picture please.
Fri Jul 09, 2021 2:06 pm

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Fri Jul 09, 2021 2:06 pm linkquote
where I did the black line on th epic below, because If i remove the hose the tee will have an exposed end where c used to be, should I leave it exposed or cap it?



⬆️    About 1 year elapsed between posts    ⬇️
Wed Aug 10, 2022 5:10 pm

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Location: Texas
 
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Wed Aug 10, 2022 5:10 pm linkquote
New owner having similar issues. With the vacuum line off at the carb, isles great, terrible acceleration and wot is about 20mph.

Hook the vacuum line up and it sputters and dies within a few seconds. There is a slight vacuum at idle when the line is unhooked from the carb when you put you finger over the hose end.

Is the vacuum pulling the needle valve out of the main flooding it out?

Why is the acceleration so poor when the vacuum line is unhooked? Is it not lifting the needle?
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