Modern Buddy

First, let me start by saying this:
1) I've read every thread (probably) here regarding the stalling issues in the 4T (and 2T), and,
2) I'm fairly proficient on things mechanical, and,
3) Until now, all service was conducted by my dealer.

My scoot is a 2012 Stella 4T, that I bought brand new in 2012. I first noticed the issue within the first few months after I bought her. At the time I thought that it was just low on gas, switched to reserve, and all seemed to be fine. I really didn't think much about it at the time. I just made sure that she was full and everything seemed to be fine.

A few times after that, I noticed that she would stall when stopped. After she stalled, it took a little too much effort to get her started again. I just dismissed this because she seemed to run ok after it restarted.

In September of last year, my scoot almost left me on the side of the road. I rode her to work that day (about 22 miles one way) and on the way home she stopped. Here's what happens: the problem starts at speed, 45-50 mph, and she just cuts out and starts again. If you keep the throttle twisted, she cuts out and starts repeatedly, until she finally just quits. After I waited long enough she eventually started again, but on the way home she sputtered, lugged, and hesitated all the way.

I mentioned this to the dealer when I had her in for service. They said that it was a simple carburetor adjustment and that the issue was fixed. When I got her home, I took her off of the trailer and rode her down the road. I only went 1/4 of a mile before the problem started again. Rather than trailer the scooter 1-1/2 hours back to the dealer, I decided to try to fix her myself.

After reading many, many threads on this topic, here's what I tried: disconnected evap system, vented gas cap, took carb apart and cleaned main jet, and replaced spark plug. This seemed to fix the problem, until I put about ten miles on her, then it started again.

Now I'm moving away from the fuel system to the ignition system.

My current problem is that I would like to replace the ignition coil and the CDI, but with aftermarket/performance parts. I don't want to put the same junk back on again. I've read in a few threads about replacement coils and CDI's, but when I contact those vendors/manufacturers about those parts, they tell me that those parts are not compatible with the 4T. What parts would anyone here recommend?

I'm also thinking about pulling the flywheel and replacing the stator. I know that the stator can be diagnosed first, but i'm thinking that the replacement stator would cost about as much as buying the diagnostic equipment.

All that I want is to ride my scoot trouble free for a few miles. I don't think that's too much to ask.

Any help/thoughts would be appreciated.

I know you took apart and cleaned the carb. Did you replace the float bowl and needle?

As for an aftermarket ignition coil, I have this on my 2012 4T:

http://www.ebay.co.uk/itm/High-Power-Ra ... 2391540296

This supplier is in the UK, but you can search around eBay for this item using the same terms. Just look for LML 4T in the compatibility charts that usually are listed in these auctions.

Did not replace bowl and needle. To be honest, they looked perfect, but I'm open to any and all suggestions.

Thanks for the reply.

Doobby wrote:Did not replace bowl and needle. To be honest, they looked perfect, but I'm open to any and all suggestions.

Thanks for the reply.

I had a similar issue with my 2T Stella. Once I replaced the bowl and needle (both of which looked fine on first inspection), the issue cleared right up.

Good luck!

Also check the grounding of your coil and the connections from the CDI to the coil. The connection from the CDI to my coil (at the coil end) is pretty much taped over and is not moving bar human help.

I would check the connection of the wiring harness off the back of the engine from the coil. Mine were loose, and caused a similar issues to yours after a mile or so down the road, or whenever the engine warmed up fully.

ArgonV wrote:I would check the connection of the wiring harness off the back of the engine from the coil. Mine were loose, and caused a similar issues to yours after a mile or so down the road, or whenever the engine warmed up fully.

+1

Thanks for the suggestions. Finally home this weekend and plan to check out everything. I'll update everyone on my progress.

Stilts wrote:I know you took apart and cleaned the carb. Did you replace the float bowl and needle?

As for an aftermarket ignition coil, I have this on my 2012 4T:

http://www.ebay.co.uk/itm/High-Power-Ra ... 2391540296

This supplier is in the UK, but you can search around eBay for this item using the same terms. Just look for LML 4T in the compatibility charts that usually are listed in these auctions.

Hey Stilts, I checked out the coil that you suggested, but they will not ship to the US. Any other suggestions?

Ok, everybody, I have another question. Read in a thread to check the routing of the fuel line to make sure that it doesn't have any kinks (figured that I would start with the fuel). So I broke the fuel line in two at the filter and let the fuel line fall into a straight line on the other side of the bike. The line was now in a straight, unobstructed line. Out of curiosity I opened the petcock to check the flow and I was completely surprised. This is a 1/4 id line and the fuel barley ran out of the line. At least not at a volume equal to a 1/4 line. I turned the petock over to the reserve and let the tank completely drain. It literally took 30 minutes to drain about a gallon of gas out of the tank. To me this doesn't' seem right (just so everyone knows the gas cap was OFF, so no vapor lock). At the (terrible) rate that the fuel was leaving the tank, once you put a bend in it and run it through an inline filter, I'll bet that the carb can consume fuel at a rate faster than it can get it from the tank. I took a short video of this. If I can figure out how to upload a video clip I'll post it here.

Anybody else seen this? Anybody ever have an issue with the petcock? There's also a filter upstream to the petcock. Any issues here?

Thanks for the continued support and help.

I eliminated the inline fuel filter and ran as short of a hose as I could from the petcock to the carb.

Doobby wrote:Ok, everybody, I have another question. Read in a thread to check the routing of the fuel line to make sure that it doesn't have any kinks (figured that I would start with the fuel). So I broke the fuel line in two at the filter and let the fuel line fall into a straight line on the other side of the bike. The line was now in a straight, unobstructed line. Out of curiosity I opened the petcock to check the flow and I was completely surprised. This is a 1/4 id line and the fuel barley ran out of the line. At least not at a volume equal to a 1/4 line. I turned the petock over to the reserve and let the tank completely drain. It literally took 30 minutes to drain about a gallon of gas out of the tank. To me this doesn't' seem right (just so everyone knows the gas cap was OFF, so no vapor lock). At the (terrible) rate that the fuel was leaving the tank, once you put a bend in it and run it through an inline filter, I'll bet that the carb can consume fuel at a rate faster than it can get it from the tank. I took a short video of this. If I can figure out how to upload a video clip I'll post it here.

Anybody else seen this? Anybody ever have an issue with the petcock? There's also a filter upstream to the petcock. Any issues here?

Thanks for the continued support and help.

Shoot some compressed air up that fuel line into the petcock.
That might clear out any obstruction.
Then try fuel flow test again.
There might be a glob of corn gunk in there.
Good luck

Does this mean, Jimbob, that you agree that this is insufficient fuel flow? Shot some air in there last night, but still need to test flow again. I think the best course of action is to remove the tank and petcock to make sure that everything is clean and clear.

This must be an issue elsewhere, because SIP Scooter makes a fast flow fuel tap.

I think the fast flow are for 2t bikes with aftermarket/big carbs

Doobby wrote:Does this mean, Jimbob, that you agree that this is insufficient fuel flow? Shot some air in there last night, but still need to test flow again. I think the best course of action is to remove the tank and petcock to make sure that everything is clean and clear.

This must be an issue elsewhere, because SIP Scooter makes a fast flow fuel tap.

Doobie, the way you described it, I agree that the fuel flow is very weak. It shouldn't take you 30 minutes to drain a tank. I think you are starving carb.

Thanks, Jim. Just want to make sure that I'm not crazy.

Just in case anybody's interested, heres a link to a short video clip. The fuel line is approximately 1/4" (6mm for you metric's out there) inside diameter. the stream of fuel that you see in the clip is only about 2-3mm in diameter (if it's proper to think of it this way?). This is true for the "On" position and the "Reserve" position.

https://youtu.be/7dL5J5VhgEQ

you my find some help from the guys on the other side of the pond. http://lmlocgb.co.uk/phpBB3/index.php

Doobby wrote:Just in case anybody's interested, heres a link to a short video clip. The fuel line is approximately 1/4" (6mm for you metric's out there) inside diameter. the stream of fuel that you see in the clip is only about 2-3mm in diameter (if it's proper to think of it this way?). This is true for the "On" position and the "Reserve" position.

https://youtu.be/7dL5J5VhgEQ

Is this how YOURS looks? Iz this your vid of your fuel delivery?
Or a video that you found?

Jimbomb, that's a video of mine. Again, that in the full "on" position.

Blew some air through the line, but I went ahead and removed the tank and will remove the petcock/fuel tap. This way I can clean the screen/filter and also check for other obstructions. Just waiting on the wrench to show up in the mail.

I'll keep everyone posted.

Lots of dudes in the UK and Italy are putting fuel pumps on their rides.

Stilts wrote:

Doobby wrote:Did not replace bowl and needle. To be honest, they looked perfect, but I'm open to any and all suggestions.

Thanks for the reply.

I had a similar issue with my 2T Stella. Once I replaced the bowl and needle (both of which looked fine on first inspection), the issue cleared right up.

Good luck!

Is it possible that the float is stuck like the bowl is full? There could be a little varnish stuck on the float hinge. Drop the bowl and rock the float up and down make sure it is free to move. That can account for filling up, gets the bowl filled and then stalling after a period of time.

Doobby wrote:Hey Stilts, I checked out the coil that you suggested, but they will not ship to the US. Any other suggestions?

This is the one I ordered: http://www.tassoparts.co.uk/cgi-bin/sto ... =&uid=5474

In case anyone is interested, I think that I've finally fixed the problem.

After replacing the stator, the problem still persisted, but in a different form. I think that I found out that I had two problems. Replacing the stator fixed one problem, but exposed the other. (I did confirm through testing that the original stator was bad).

After replacing the stator, she ran like a striped A$$ ape, but for only about 3 or 4 miles, then she would die. If you look earlier in this post, I linked to a video of the fuel coming out of the fuel tap. Needless to say the flow was very weak. I bought a fast flow fuel tap from Scooter Infinity and swapped it for the stock fuel tap. Be advised that it required a little modification (I would be happy to explain this if anyone is interested). The fuel flow from the fast flow is NOTICEABLY better.

I've been taking extended rides for the last two day for shakedown purposes. I'm happy to report that the problem seems to be gone.

I'm still waiting on other replacement ignition parts to arrive from TASSO (CDI and HT Coil) as well as a new carb. These were the next parts that I was going to swap if the problem wasn't solved. Still may install them anyway.

Hope that this helps someone that's been having similar frustrating problems.

I had stalling issues with my 2012 4T...
solution:
when the fuel line come down from the tank to the cut off valve it arches back up to drop down into the carb, at (or near the top of that arc) is the filter, fuel isn't filling that bell shape of the filter high enough to go into the outflow to the carb, so it acts like its starving.

the lines are about 1" too long and the bell shape filter could easily be replaced with a smaller diameter (generic from auto part store) for a couple of bucks (also, if that's the original filter, it'll need changing anyway).

That's what I did and haven't had an issue since. been running like it was new.

After many shakedown rides, I'm happy to report that the problem is fixed. I would pose this question to anyone on the forum: Why did this problem start? What changed?

When I first got her in 2012, she ran fine, but on occasion she would act like she was out of fuel, but switching to reserve seemed to fix it. Over time this got progressively worse. I'm just not sure why. Any thoughts would be appreciated.

Just to be clear, I tried all of the venting/supply line fixes, but none of them worked.

The stalling would happen to me occasionally. It would always happen if I put too much gas in the tank. It would also sometimes randomly occur. One day it stopped and I never put much thought into it. However, one day when I took the cowl off the right side I noticed the rubber line from the evap system into the air hose had basically broken off. It look like pressure caused it. I closed the hole to the air hose with gorilla glue and left the evap hose off. Ever since I haven't had any problems. I don't know if it is a random occurrence or if it had a link to the stalling problem.

doobby,
Probably just crud in the petcock. I don't know what (if anything) is different between the 2t and 4t fuel valves, but this does occasionally happen on old Vespas.

I *suspect* (do not know for a fact) that the fuel valve in your Stella uses virgin rubber, and therefore is incompatible with Ethanol. If that's the case, then the rubber would break down over time and clog the valve.

Best,
-Slashy

[quote="srbbnd"]The stalling would happen to me occasionally. It would always happen if I put too much gas in the tank. It would also sometimes randomly occur. One day it stopped and I never put much thought into it. However, one day when I took the cowl off the right side I noticed the rubber line from the evap system into the air hose had basically broken off. It look like pressure caused it. I closed the hole to the air hose with gorilla glue and left the evap hose off. Ever since I haven't had any problems. I don't know if it is a random occurrence or if it had a link to the stalling problem.[/quote]


srbbnd, I've been having a similar issue with my evap. It was disconnected when I got my scoot, but it was seeping gas (!) slowly onto the body. So I reconnected it following the diagram in the glovebox. Now, the bike stalls after 10 minutes of running with it connected. Once I disconnect it, she runs fine. Is the "gorilla glue" solution working out fine? And has the rest of the evap system been leaking for you at all? I'd like to just bypass it altogether...

Here is a link to a thread I started in the past.

http://www.modernbuddy.com/forum/viewto ... highlight=

It has a pic of what became disconnected. I put gorilla glue on the air hose/manifold hole. I did not seal the small tube. I have not had any leakage that I have noticed.

I have had several come thru with paint flakes clogging the fuel filter. Make sure to check there as well.