Dramatically slow after carb clean! Help?

swillscooter · Post by **swillscooter** » Thu May 13, 2010 1:40 pm

So I dropped my scooter and my wife's off to our local dealer for some spring maintenance. My scoot has 3000+ miles and runs like a top - just needed some oil and and inspection and I was all set. My wife's is a different story. She's only got about 700+ on hers and didn't get out on it much at all last year. After winter, I tried to start it up and after some difficulty, it would only stay running with the throttle pretty wide open. So I rode it in (cringing at stop lights as I held the throttle open and the brakes tight!) and discussed with the dealer the issue and the history (not much riding, probably a dirty carb, etc.) When I picked it up yesterday, I was told that yes, the carb was the culprit and it had been cleaned, oil changed and ready to go. Took mine home first, then came back for my wife's. As soon as I pulled out I knew something was off. The scoot (a 125) will only get up to about 35 MPH wide open, and it struggles to do even that. Of course, the dealer is only upen until 5pm (beacuse that makes sense for people that work!) so he was gone at this time. I'll need to bring it back in, but I'd like to have some idea of what could be wrong. Clearly this dealer doesn't belive in quality control or mechanic test drives after service, so I need to know what might need to be done. Any ideas? Any other questions I should be asking?

BuddyRaton · Post by **BuddyRaton** » Thu May 13, 2010 2:25 pm

Give them a call. I wouldn't jump to conclusions about the dealer or mechanic. Lets be honest here...there is a very very very good probability that the problem were caused by not properly winterizing...sometimes called neglect.

If you noticed it "As soon as I pulled out" it would probably have been a good idea to turn around and demonstrate the problem.

Work with them and it should be sorted out quickly.

If you really don't trust the quality of work you should go somewhere else. The warranty will be honored by any authorized dealer.

swillscooter · Post by **swillscooter** » Thu May 13, 2010 2:44 pm

I'm pretty sure that the problem was acually caused by not "summerizing!" Since it wasn't ridden enough last year (is there really ever enough?) I think it got build up in the carb just like it would if it were sitting for the winter. I did winterize both scoots (seafoam, full tank, battery tenders) but my guess is the gunk was already built up at this point.

As to turning right around to demonstrate to problem, that would have been difficult as the shop was then closed and the owner gone. My primary beef is that it would have been such a glaringly obvious issue IF it had been ridden to make sure it worked. I was called and told that it was "ready." Is this considered ready? What if I had brought it in because the brakes weren't working? Would adjustments have been made without testing and it called "ready?"

Look, I'm not trying to slag the dealer here, nor was that the point of my post - you'll notice that I do not publish my location, I have not mentioned the dealer name, etc. I just feel that we're dealing with a vehicle which, for the sake of safety, needs to be performing at the level that the operator (in this case, my wife) expects. Additionally, past interactions with the dealer have not left me with a high level of confidence - but I do not feel the need to get into those here.

So that I am as educated as I can be about the possible causes of this problem, the question from my original post remains...

Since the carb was cleaned, what else could be causing the issue (max speed of 35 on a 125cc)? Thanks!

Mark2000 · Post by **Mark2000** » Thu May 13, 2010 3:35 pm

I'm going to agree with Swillscooter. I've brought cars into too many mechanics that claimed to have fixed a problem and I'll find it again a few miles from the shop. It seems like their way of getting you back for another round of tests and more money spent. Either that or they are just lazy.

I know this is still on warranty, but be very weary with these mechanics when it's up. Mechanics should make sure something is fixed before they send you home with it.

charlie55 · Post by **charlie55** » Thu May 13, 2010 3:59 pm

I had a similar problem after re-jetting my carb. What it boiled down to was re-assembling the jet needle, slide spring seat, and slide spring incorrectly. The following diagram (for a generic cv carb) shows these are parts 4, 5, and 3, respectively.

As you can see, the needle is supposed to fit below the spring seat, which in combination with the spring, provides some resistance to the pin's upward motion (helping to control the mixture). My mistake was that I placed the pin through the seat, such that it's flat head was above the seat. This resulted in the pin basically being able to bounce around in an uncontrolled manner. The scoot ran like crap, wouldn't respond well to the throttle, and refused to get past about 25-30 mph.

This may not be the cause of your particular problem, but it's something to consider.

swillscooter · Post by **swillscooter** » Thu May 13, 2010 4:05 pm

WOW, Charlie55 - that's a great lead! Did you just have to reassemble it correctly and that was the fix or was there damage done in the process? Do you think I'm safe to drive it back to the dealer (approx 7-ish miles)?

charlie55 · Post by **charlie55** » Thu May 13, 2010 4:34 pm

The mistake didn't cause any damage, so correct re-assembly was all I needed to do.

I don't believe that it would do any physical damage, but the erratic behavior of the engine might make the ride a bit on the unsafe side. If you're dead-set on riding it back to the dealer, try to pick a route with as little traffic as possible so that you can safely accommodate that behavior.

swillscooter · Post by **swillscooter** » Thu May 13, 2010 6:06 pm

Well, here's the current update....the dealer agreed to come and pick up the scooter and will be looking into the problem. The mechanic also called and offered an apology which was very nice. I'm sure that my after-hours irate phone message last night forced some of this action but regardless, the response (customer-service wise) was my best case scenario --- dealer pick-up, fix correctly at no additional charge.

I hope that the dealer will add mechanic test-drives to his servicing process. I know that I will add pre-payment test drives to my process (as are provided for by my state's laws.)

Because everyone is always so helpful on this forum, I'll be sure to re-update this thread when the root problem is identified. Thanks again!

swillscooter · Post by **swillscooter** » Sat May 15, 2010 12:09 pm

Here's the update....The dealer picked up the scoot and the mechanic identified the problem as a "faulty vacuum seal." If someone could help me out and possibly identify what part that is on Charlie55's handy exploded diagram of the carb, that would be great.

Anyway, the mechanic fixed the issue and delivered the scoot to our house last night. I took it for a test ride immediately and it seemed to be back to normal. I'm sure the root cause was the lack of street time that it saw last year, so we'll have to remedy that this summer. Thanks again for your help!

charlie55 · Post by **charlie55** » Sat May 15, 2010 1:05 pm

If I had to guess, it'd be the top of part #6. The entire part is a slide, but the top is a rubber diaphragm that seals off and divides the vacuum and atmospheric portions of a CV-type carb. This diaphragm must be correctly seated so that it forms a proper seal.

But, as I said, I'm only guessing. The term "faulty vacuum seal" is pretty vague, and could have a few meanings. Personally, I'd have the shop owner or mechanic show me exactly what they were talking about as it could save you some bucks in the future when you're off-warranty and a similar situation develops.