MC250 Roketa wont start

[nioleptix]

So I bought my mp-250a-jcl about a year and a half ago and put about 1500 miles on it since. It sat up in my garage during the off season and when i tried to start it up again to ride, nothing happened. After replacing the battery, completely cleaning out the carb, and replacing the fuel filter, still nothing. It will momentarily start if i spray carb cleaner into the air intake, but then quickly die. Any suggestions guys (and gals)?

[wile]

Yes, your Pilot jet and or passage are clogged. Did you drain the gas while it sat there for months, or did you ever go and start it up once a week and warm it up.
You will have to take the carb off and clean the JETS AND PASSAGE not just the jets spray into the holes the jets came out of and spraying into the Pilot Jet slot spray should come out by the front of the carb by the BUTTERFLY. There are tiny holes by the BUTTERFLY that suck the gas out from the pilot jet.
Wile

[nioleptix]

Yeah, earlier today, I took the entire carb off, removed the main and pilot jets and let them soak in carb cleaner. I completely cleaned out the carb with carb cleaner until it was nice and shiny and then let it dry. After soaking the jets in carb cleaner for a bit, I took a small wire and poked all of the tiny holes to make sure they werent clogged. I then reassembled the whole shebang, and then, still nothing.

Like I said, I can spray carb cleaner into the air intake, and it will start for a second, and then quickly die.

[wile]

Ok, so we will assume the passages and jets are clean. Now we have to see if gas is getting into the carb.
Take the Fuel Line off the carb and put it in a container and crank the motor and fuel should stream out. If it doesn't then take the Fuel filter off and try it again, if now the fuel streams out your fuel filter is clogged. If still no gas then it is your Fuel Pump or your Vacuum line going to the Fuel Pump.

IF gas does stream out when you crank it NOW we need to check if gas ACTUALLY is filling the carb bowl. Loosen the Bowl Drain Screw and see if gas comes out. Leaving it open crank the motor again and gas should still come out that will tell you all is pretty good with the gas flow to the carb.

If all is good from the above NOW we are back to the CARB, turn the Fuel Ratio screw clockwise until it stops then turn it COUNTER CLOCKWISE 2 1/2 turns and give that a shot.
Wile

[nioleptix]

I have the linhai horizontal engine. Where might the a/f screw be?

[wile]

If your carb looks like this then it is by the INTAKE UNDERNEATH which is a pain to get to.
Wile

[nioleptix]

Thanks for the pics!!

Well, I wish I would have done that earlier when I had the carb completely off. Ill give this a shot though!

Thanks!

[wile]

Good luck man, let me know if it fixs the problem but SINCE it fires when you spray into the intake it is a Fuel Delivery Problem.
Wile

[nioleptix]

Okay, I went ahead and adjusted the a/f ratio screw to 2-1/2 turns out, but still no go.

Do you think it would be worth replacing the vacuum lines? If so, is there a place where I could find a diagram of these lines?

Muchos gracias.

[wile]

Nio,
If you tested the fuel flow from the petcock to the carb like I mentioned they are fine.
You do have the AIR FITLER connected right?
If so DO THIS crank the sucker then take the plug out and IF it did not FIRE the PLUG SHOULD BE DRY, which comes back to the carb, not sucking in gas.

Now If it is WET then the SPARK PLUG IS NOT FIREING.

Let me know because then It still points to the PILOT JET, you did spray INTO THE Pilot Jet and SAW SPRAY COMING out by the BUTTERFLY? If Spray doesn't come out the TINY HOLES by the ButterFly the PILOT JET AND OR PASSAGE ARE Clogged.

What I always say to use it a SPRAY CAN OF CARB CLEANER they come with a THIN LONG straw, Take the Pilot Jet out and stick the STRAW into the HOLE and With your hand OPEN THE BUTTERFLY just grab the Wheel and SPRAY into the Pilot jet hole and Spray should come out from the tiny holes by the butterfly.
Wile

When you Spray INTO the PILOT JET HOLE here is where spray should come out:


When you Spray INTO the MAIN JET HOLE here is where spray should come out:

[nioleptix]

Jul 1, 2012 21:42:50 GMT -5 wile said:

Nio,

If so DO THIS crank the sucker then take the plug out and IF it did not FIRE the PLUG SHOULD BE DRY, which comes back to the carb, not sucking in gas.

Now If it is WET then the SPARK PLUG IS NOT FIREING.

Wait, so either way, the spark plug should be dry?

[wile]

Nio,
If your cranking it Gas should be going into the motor, Now if it DOES NOT FIRE, the plug should be WET(means the Spark Plug is NOT SPARKING).

If your cranking it and IT DOES NOT FIRE and the PLUG is DRY(means you gas is being sucked into the motor).

If your cranking it and it DOES fire the plug should be Dry.
Wile

[leo]

things i would check based on what has been posted:
pilot jet. clean with straight pin, guitar string, or stripped bread tie.
auto choke. your idle might be set too low for your engine to start without it or the mixture too lean.
manifold leaks. this includes vacuum lines, manifold mounting bolts, rips and tears in the manifold.

BTW, it's never a good idea to soak your carb in carb cleaner.

[nioleptix]

Might there be a diagram anywhere online of the vacuum lines/manifolds that I might need to check? As far as I can see, all of the vacuum lines are in place and no cracks are present.

Also, the pilot jet was cleaned yesterday.

[richardthescooter1]

Make sure your ignition coil is tight, yesterday I had a hard time starting my scoot, check the ignition coil end to spark plug, found that little wire inside was pushed out of place (no connect) then as I was working coil came lose in my hand, tigten the wire replaced with a snap on cap, working good now.

[wile]

Jul 2, 2012 10:35:34 GMT -5 nioleptix said:

Might there be a diagram anywhere online of the vacuum lines/manifolds that I might need to check? As far as I can see, all of the vacuum lines are in place and no cracks are present.

Also, the pilot jet was cleaned yesterday.

The Pilot jet was cleaned BUT WAS THE PASSAGE CLEAR, did spray come out in front by the Butterfly. People just clean the jets but where the fuel comes out the holes are TINY TINY TINY and very easly get clogged.

You have NOT CHECKED how the PLUG IS after cranking THAT WILL TELL WHAT THE PROBLEM IS. EITHER YOU HAVE NOT SPARK or you still not getting gas sucked out from the carb.

You have to CHECK the plug after cranking and no start.
Wile

[richardthescooter1]

I have carb question. when turning my idle screw, I get no or very little responds, does that mean the jets are clogged?

[wile]

Richard,
Not necessaryly, it could be your Fuel Ratio Mixture is not set right. So the first thing you want to do is TRY and adjust your Fuel Ratio to GET the HIGHEST IDLE from where it is Currently set.

First Start up the Scoot and let it warm up At Least 5 minutes so the ENRICHER cuts off the Extra Fuel.

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. 1. 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***

Wile

[richardthescooter1]

I do have it 2 1/2 turns out, and it idles good, just when I turn down the idle, it take a day for it to work down. I have the carb that is a pita one and don't have the right tool yet to adjust it the proper way.

[wile]

Richard,
2 1/2 turns out is JUST A STARTING POINT, if a person is having trouble starting it the 2 1/2 turns out is a good setting and if everything else is working good the SCOOT WILL START and usually stay running. But that may NOT BE the right setting for that scooter, All the motors and things on it are different.

So if the IDLE IS SLOW TO COME DOWN IT IS TO LEAN.
So the #1 procedure I posted above should fix that.
Wile

[richardthescooter1]

Ok thanks wile. We will try it.

[wile]

Good luck it is just a minor adjustment that is all nothing major.
Wile

P.S Get yourself a small screwdriver set like this works great for your purpose:
www.harborfreight.com/8-piece-right-angle-screwdriver-92630.html

[richardthescooter1]

ok, thanks

[nulldevice]

I may have missed this in the posting, but -- Did you make sure the gasoline is making it from the gas tank to the carburettor bowl?

Disconnect the fuel line from the carburettor and the fuel valve vacuum line from the manifold and suck on the vacuum line and hold that vacuum. You should get fuel flow. If not it may take a minute or so for the fuel to flow from the tank, fill the fuel filter and line.

If you get fuel flow connect the fuel line back up, open the carburettor drain and suck on the vacuum hose again. You should get fuel out the carburettor drain. If so, close the drain, hold the vacuum to the fuel valve for a minute or so then reconnect the vacuum line.

Try to start it.

[richardthescooter1]

I notice three time my scooter cutting out at wot, backed off and it regain its self, whats going on? it acts like its running out of gas, until I back off. my fuel pump is a mikuni and I recently put new fuel filter on

[wile]

Do this Richard,
When it starts acting up BACK OFF THE THROTTLE 1/4 of an inch and HOLD IT THERE.
a. If the scoot speeds up it is LEAN(not enough gas).
b. If the scoot stumbles and or hesitates and settles down it is RICH(TO MUCH GAS).

But from the previous post of the IDLE slow to come down you are LEAN.

HAVE YOU ADJUSTED THE FUEL RATIO TO FIX THE SLOW DROP IN IDLE Following the procedure I posted? If not that alone may also fix your WOT problem as well.
Wile

[richardthescooter1]

I'll move that a/f a 1/4 turn out tonight. I did notice the other day my air box had a crack right where you put the screw in on the outside, would that have any effect on it?

[wile]

Yes, ANY AIR leaks will make it run LEAN. So First check for any Air Leaks, you can get a Spray Bottle of WATER and spray individual areas and IF THE IDLE CHANGES you found a LEAK.
Wile

[richardthescooter1]

ok, thanks wile

[richardthescooter1]

Found the leak, my clamp that holds the hose to airbox of loose. tighten it up, scoot is working good again.