Modern Vespa

Hi Everyone!

I got a 2019 Liberty 150 and I need some help. I purchased it from someone who let it set and didn't treat the gas nor use the right octane. It started hard, ran rough no matter what, and check engine light would pop on. Here's what I've done to it:

- New iridium spark plug (from/per scooterwest)
- New OEM air filter
- Adjusted intake/exhaust valves to 0.004
- cleaned the throttle body
- new battery (and kept unplugged overnight to reset ECU)
- ran fuel cleaner (redline) through system
- removed the fuel injector and ran carb cleaner through it (according to robot's video engaging it with 12v)

I've put about 1K miles on it now. Once the engine is warmed up, it runs like butter. Accelerates good, idles good, etc

But...if the engine is cold (ie - not been run for at least a few hours), it can take 2-4 seconds of starting to get her going and she idles rough. By rough, I mean I can hear small rpm adjustments up and down and it just seems too low of rpms. Once the engine is warm, the idle is stable at a bit higher rpm. Ocassionally it'll stall on the initial idle or the check engine light would come on if I left to idle. Happened all the time before I did everything in my list above, but not it's less frequent. Again, take it down the road for 3-5 min, and it's all good.

Anyone have any ideas? It's not "terrible" but would like to have it idle smooth at start-up and take a little less cranking to start. Thanks for any insights!

There may be some crud/water in the gas tank if you did not completely clean out the tank, the O2 sensor may be a little wonky too. But if you say it runs pretty good, I would just take it for a nice long ride.

Well, I've put one 1k miles since I got it and have been running it at least a few hundred miles since i did my list above. So, I'm doubting just running it more will fix. I'll do some digging on the o2 sensor.

I've seen some posts about the evap canister/system can cause rough idle and start. I tried starting with the gas cap off to ensure no pressure was in the tank, and it didn't behave differently. But, maybe something in that system could still be effecting things? I'm running out of things to check…

Rough extended start could be the valves.
I see you checked em and got the right setting.
But could you have moved them when turning the lock nut?
Just a guess. Seen it happen even with experienced wrenchers.

I've actually done the valves twice for that exact concern.

I made sure 0.005 could not fit, and just 0.004. I know it's subjective, but I think to make that happen, there's still some decent drag with a 0.004 feeler. Some say to make the exhaust different, but the spec on the scooter says 0.004 for both intake and exhaust, so stuck with that.

Slightly loose is better than slightly tight...

Well, guess I can check the valves again just to be sure.

The closest Vespa/Piaggio dealer wanted $500 to just check the valves so scared to take the scooter to them and to see the bill!

When I cleaned the throttle body, I noticed a small black tube outside the butterfly valve that must be for air for idle (as the butterfly is shut tight with no throttle). Is there anything along that route to clean or check on?

Yes! https://cheekythoma3.wixsite.com/itsme/idle

Ok, the Liberty has a different throttle body than that article, but I'll take a look and see where things go if I can clean something like it's mentioning. Thanks for that!

Also, I wonder if I adjusted to 0.004 but a little on the tight side, so I'll pop the cover and check again with the feeler gauges.

Well, I see there's a foam filter in front of the valve that controls the idle. It goes there I circled in the top of the image. I really didn't notice it when I put in a new fitler. It really smelled like oil and I think had a bit of oil in it. I pulled it out and cleaned it really good with carb cleaner. That square thing in the filter goes to a compartment with a fair amount of oil that collects in a tube. I think this is similar to what the vespa call their "bubble". I'm hoping this may helps things cleaning all that out.

Here's the "valve" for the idle that the foam filter sits in front of. I think it's actually a stepper motor thing. Is it worth cleaning too? I checked for them new and it was like $180

If I can figure out how to get it off, maybe I'll get some cleaner in there. I'll avoid throttle body cleaner as it's not good on rubber and plastic, maybe just some carb cleaner. The thottle body to the right already have been disassembled and cleaned.

Ok, didn't get to the valve clearance checking, but cleaning out that little foam block and what I could of the valve inlet and outlet, it started right up and doesn't sound like it's revs slightly up and down anymore. I'll feel better doing it again tomorrow and having the same result. Does the initial idle sound good? I don't have a baseline Piaggio/vespa to compare it to. Maybe I fixed it? I put a short clip of doing the startup below.

https://youtube.com/shorts/xi6qi1PomEc?feature=shared

EDIT - repeat test, started quick again, yay, but idle still off unlike first time. But maybe ECU reset is part of it. Worst case, will check valves next.

There was recently a thread about a Liberty 50 with issues that turned out to be the canister purge valve. Just something else to look into.

2020 Liberty 50 with 450 miles on odom surges at idle.

Thanks skids for the link. I found that post last week, and I'm assuming the purge canister wasn't letting pressure release from the tank, as he disconnected it to fix. So, to test that theory, I took my gas cap off (to relieve any existing pressure) and then started it with the cap still off. It didn't change behavior, so I think...it's not the evap system?

Busy treating my MIL this eveningas I read your post...but I will suggest that you relax or the valves. You've got 'em correct. And your fuel is not the issue.
Perhaps it experienced an overfilling at the gas pump? Messing with the evap system.
Will toss some ideas tomorrow.
(7 yrs experience with my Liberty150i)

O.S.

Thinking about your dealer charging $500 to do the valves. Crazy of course....
But how much would they charge to plug your scooter into their diagnostic tool?
Walk out of there with a health report on your engine.
O.S.

Guess I could call them and ask, just got turned off quick by the valve quote. There's another much better dealer I trust, but they're 3 hours a way, so kinda trying all other avenues first. And there's a kind of DIY victory I want after everything I've tried, if possible.

I have a obd2 Bluetooth car reader and tried picking up a fiat adapter to the 3 pin connector on the Liberty but it won't connect. Bummer as that would have been awesome to get working.

Valves are not hard. Robot has a few different videos and here is my write up on the valves on a Liberty 150. Here is a link to a thread with my post last detailed written instructions and pictures.

It just takes time to remove the body panels for access again Robot has the videos.

Valve adjustment on first service? (Page 2)

It seems he has got the valves set correct.

EVAP issue should clear up after a long ride or a day with short riding. This would cause the CEL to come on too.

Less likely but faulty throttle body setting could cause this issue.

I don't know this machine, but if that is not the injector in the pic, I would guess it is a MAP sensor. Like I said, just a guess.

OK, so where are we?...
is your idle still as good as it sounded in your youtube?
Because that sounded perfect!

O.S.

You're great OldSchooot!

Idle did sound perfect in the video, thanks for confirming! Wasn't sure if that was the right RPM or not.

I've done a few startups since with a cold engine, and there's some roughness (though less) mixed in at times, but improved. So not at good as the video, but it does seem to be starting much better! ie - less cranking. So, solid win there.

Watching the valve videos and reading the links, I definitely adjusted the valves tight .004, so I think I'll adjust once more just to feel better and see if that tweaks the idle issue even better. Needed to order a new set of feeler gauges (as I borrowed some last time). So, should be able to get that done in a couple days.

I'm feeling much better about things! I love Piaggio, but it can be harder being less common for maint info (especially the Liberty, most folks have vespas).

The Liberty owners are out riding and taking photos while us Vespa owners are posting on the forum.

Ooops, time to go get a scooter tag from another forum