Trouble starting, runs choppy By jonas66 (Read 1,620 times)

[jonas66]

Hello, I am new to this board, but as I've been googling my particular scooter problems I keep stumbling across links, so I thought this would be a good place to start.

I have a Roketa MC-17 150cc Sicily scooter. I have very little experience at self-repair of any kind, but the shop I was taking it to is, unfortunately, staffed by very sloppy, unprofessional mechanics who do not seem to fix the problems, and usually add one or two in the process.

Here is the background: My bike was left sitting in a warehouse for a week or so because we had to move on very short notice. When I went to start it up, it would start fine but upon throttling would immediately die. I took it to the mechanics, who looked at it and decided that it needed a new carburetor, as the previous had become clogged due to the ethanol content of gasoline. They replaced the carb, and replaced the stator that they said had gone bad (this last without my authorization).

I got the bike back and drove it home, and it was apparent on that drive that there was some hiccupping of sorts as I approached the top speed, and it would not go as fast as it used to go. (45mph, used to be 55). It also had the idle screw set so far out that without throttling at all the bike would go forward at least 5-10 mph on its own.

The next morning, and since then, I've had a lot of trouble getting it to start. Starting off the ignition switch does not work, I have to kick start it to get it to do anything initially. When it does start it is very cold, will die multiple times, and again if I over-throttle it dies. I can, eventually, get it to start moving, and then it runs very choppy for a while, and even when fully warm it still stutters a little, more so at the top speeds.

Searching for answers, it seems like there's a number of things it could be, but the likely answer is that the carb needs tuning. I was hoping I could get some troubleshooting, and potentially an explanation on what I can do to start fixing this sort of thing myself. But like I said, I have next to no experience with self-repair, so I'm sort of starting from scratch, and I don't know where I can find any good manuals to help me.

Any help would be greatly appreciated. I don't want to give the mechanics any more of my money, and there are not a lot of options in my town.

[Kaveman]

Check the forums help section !! There are several different trouble shooting guides that may help you figure this out !!Vacume leak ?? Too much air ( carb mounting gasket not tightened down properly ? do you still have the stock airfilter installed ?
will c.

[jonas66]

Thanks. I'll take a look at that section and come back with more refined questions. I did notice a recommendation to purchase the Haynes manual for Chinese scooters. Is that a good place to start?

[Alleyoop]

Welcome to the forum Jonas66,
And your right most scooter shop mechanics are only there to replace parts and not fix a simple thing. You really did not need a new Carb unless the thing is old and was crudy looking. The carbs are very simple and only a few things need attention at times.
Alleyoop

QUESTION:
Does your Scoot have a TACH?


Yes it appears your problem is all a fuel delivery problem. Lets eleiminate a few things first with simple tests.

A. Get a Spray Bottle of Water ready.

1. Start the Scoot up and let it warm up for at least five minutes.
2. Spray individual areas, by the INTAKE MANIFOLD, by where the VACUUM hoses connect, by the AIR FILTER TUBEing where it connects to the Carb, By where it connects to the INTAKE MANIFOLD etc..
3. If the IDLE when doing this CHANGES you found an AIR LEAK and you have to either tighten Clamps and or bolts to fix it so it does not LEAK.

If all is ok now we move on to adjusting the Carb settings.

A. SET THE IDLE:
1. IT APPEARS they have the IDLE SET TO HIGH.
There is a screw on the THROTTLE CABLE SIDE it has a SPRING on it you cannot miss it, it sticks up.
A. Turn that screw COUNTER CLOCKWISE Slowly until the REAR wheel STOPS SPINNING.
B. You want the IDLE just HIGH ENOUGH that the WHEEL WANTS to start spinning.

ADJUST THE FUEL RATIO MIXTURE:

****YOU WANT TO GET THE HIGHEST IDLE POSSIBLE OUT OF THE FUEL RATIO MIXTURE****


So from where it is currently set FIRST TRY richening it up more:

1. Turn it 1/4 turn Counter Clockwise and wait about 10 seconds to allow the motor to catch up with the new setting. LISTEN or look at your tach:
a. If the IDLE GOES UP REPEAT #1, UNTIL the IDLE does not change or drops a little THEN TURN THE SCREW CLOCKWISE 1/8 and that should be the highest IDLE from the Fuel Ratio Mixture and go to #3.

**** IF ON THE FIRST 1/4 TURN COUNTER CLOCKWISE THE IDLE GOES DOWN OR DOES NOTHING, TURN IT CLOCKWISE 1/4 TURN TO GET IT BACK TO WHERE IT WAS AND GO TO #2****

2. Turn it 1/4 turn Clockwise and wait about 10 seconds to allow the motor to catch up with the new setting. LISTEN or look at your tach:
a. If the IDLE GOES UP REPEAT #2, UNTIL the IDLE does not change or drops a little THEN TURN THE SCREW COUNTER CLOCKWISE 1/8 and that should be the highest IDLE from the Fuel Ratio Mixture and go to #3.

3. If the idle is TO HIGH NOW LOWER the IDLE USING the IDLE SPEED SCREW so that your REAR WHEEL JUST WANTS TO TURN... Go to #4.

4. Now give the Throttle a quick twist and let go, the Motor should Rev up nice with no sputtering or hesitation and come back down to where you set the idle.

*** IF TURNING THE FUEL RATIO SCREW Clockwise or Counter Clockwise DOES NOTHING Then the Pilot Jet AND OR ITS PASSAGE ARE Clogged and you will have to clean the Jet and CLEAR OUT THE PASSAGE. And go through the Procedure again***

HERE IS MY CARB ON MY MOTOR and what the IMPORTANT hoses are:



HERE ARE PICTURES OF WHAT YOUR CARB LOOKS LIKE SO YOU KNOW WHERE THINGS ARE ON IT:
LEFT SIDE OF CARB:



RIGHT SIDE OF CARB:

[jonas66]

Thank you for the pictures, they are really what I was hoping to find. As a note, when I was moving it into a garage I saw a puff of smoke come from the side and found a loose hose end, so I'll also make sure that everything is connected properly. It may be a day or two before I can work around my schedule, but I will see what I can do about making those adjustments.

[Alleyoop]

Great, if you can take pictures of the top of the motor so we can see the carb and hoses and any other stuff on it. Some have emissions on them and they have canisters and hoses coming and going.
Alleyoop

[jonas66]

Well, I got the seat out so I could take a look at the engine, haven't done the spray bottle test yet, but I did take a couple of pictures for reference.

FYI, no, the scooter does not have a Tach.

View of the carb.


Here's the hose that is hanging loose. Not on the carb, on the block in front of it. I don't know if that's how it's supposed to be or not.

[mself52]

That is your valve cover blow off breather when your engine warms up some oil will come out of that so most people make a catch can for that hose to keep oil from getting everywhere including hitting the hot engine and making smoke

[Alleyoop]

First, how long ago did you take the bike to the shop? Reason I ask is because THAT IS NOT a NEW CARB, it looks like a new INTAKE MANIFOLD but the carb is NOT NEW. Look at all the pitting on it that occurs over a very long time.

But anyway, everything there looks good, by the carb and the hoses. I can see the bike has some emission stuff on it, (1) a PAIR system that is the Curved Pipe in front of the Valve Cover, you probably have an EVAP system as well which is the VENT from the gas tank going to a canister.

That hose coming off the VALVE COVER that you say just hangs put a Fuel Filter on the end of that hose and ZIP TIE it high so if it squirts oil out it will drain back down by gravity and you won't have oil being squirted under there.

Also when was the last time a VALVE ADJUSTMENT was done?

But for now lets try adjusting the IDLE and Fuel Ratio on the Carb like I posted above that may fix your problem.

Then we can fix the ELECTRIC START, because the Kickstarters are a weak point they are only supposed to be used for emergencies and not for everyday use they are not very sturdy and often break.
Alleyoop

[jonas66]

Yes, it occurred to me that the carb was not a new shiny thing. I'm not sure if they put in a used one or what, but the end result, this only adding confirmation, is that the shop won't be getting any more of my business, because they're pretty incompetent, and not very honest. I had not wanted to this time around anyway, but I was desperate and they're right by my office.

I was able to make adjustments to the idle, and tweaked the fuel ratio, and it doesn't seem to have a problem starting anymore, at least. I wasn't able to get it up to speed on my road to see if there was still the issue at top end yet. Going to drive it home and see how it does, and make further adjustments from there when I have time to tear it apart and put it back together again. At the very least, I know how to access it, and can put it back together without breaking anything. Small victories . . . .

I don't know when the last time there was a valve adjustment. For now, I'm going to tackle the fuel ratio angle, and go from there.

[Alleyoop]

Great, because at this time that is all it is running to LEAN the motor needs a little more fuel.

You say that the Electric start does not work, When you squeeze the Brake handle do your Brake lights come on?
When you get a chance and messing with the carb, Find the SOLENOID(RELAY for the STARTER) and get a ScrewDriver, piece of wire or pliers or anything and TOUCH BOTH TERMINALS on the SOLENOID and see if it SPINS the STARTER.
The Solenoid looks like this:
Alleyoop

[jonas66]

No, the electric starter DOES work, sorry for being unclear. It starts reluctantly in the morning by the starter, and takes a little patience getting it going. It's also still choppy when I start driving, but it seems like as it warms up it's top speed increases, and it becomes a little less choppy. I think it needs another small adjustment to the fuel ratio, but if these issues suggest anything else to you, I'd appreciate the feedback.

Even before, the electric starter was going. The problem was that it wouldn't start the engine.