I just tried to put a tune up on my mt50qt-2 scooter it is bogging down when i give it gas and running funny. i just replaced the o-ring gasket for the muffler and put a plug in it and it seemed like it was ok for a minute but then suddenly it started acting up again.the plug isnt oil fouled its more burned/black.?????????????? And if im running rich how do i fix it?49cc redstreak moped.Thanks Hi Don,
Your engine "should be" a 50cc GY6,far as I can tell.
Actual Mfgr of your scooter is MEITIAN,,,,
which is of little use to know because they dont deal directly with "Retail Public"
The engines are very good lil motors and are almost universally used on all sorts of scooters
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The Carbs on those things is unusually complicated for small engines,,,,,normally very simple carbs are used.
There's Pro's & Con's to that.
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It should be one of these
http://store.scootertronics.com/fostca13...
"Keihin CVK PD193 carbs with auto choke made in Japan with electronic choke for 49cc 139QMB engines used in most Asain/Chinese scooters."
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Here's a Parts Diagram which gives you an idea of where everything goes
http://www.scootusa.com/139qmb_carb_repa...
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Here's a Parts Price List
http://www.scootusa.com/139qmb_carb_4.ht...
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Normally a Leaky Float needs Float Needle /seat replacement.
Price for a bare needle is $13 + shipping
"Carb Rebuild Kit" includes needle & other stuff,like a gasket you may need=$25 + shipping.
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Here's a Whole,New Carb on Ebay.
It's from ScootUSA,,same folks who's website listed above has the carb info.
Retail Price on those carbs is $120,,,,which seems about the going price on most websites,,$100~120 or so.
Ebay Price= "Buy Now" $45 + about $12 Shipping
Bid Starting at $25
http://cgi.ebay.com/ebaymotors/CARBURETO...
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No Sales Pitch from me on that carb on Ebay,,I just mentioning it.
But that's a heckuva deal,,,especially if nobody bids on it and it stays cheap.
Even Buy-it-Now $44 is Cheap.
You can see for yourself what rebuild/repair parts would cost.
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As everyone has already said,,,Your Scoot is Running Rich.
If that happened Before you worked on it,,,or was the reason for working on it,,,
#1 Suspect would be a Leaky Float Needle.
That allows fuel to overflow the carb bowl & go straight into engine----waay to much fuel.
The CHOKE was also mentioned.
Those carbs have an Electric Choke,,,which raises a bunch more suspicion & possibilties than a conventional "manual choke".
Try switching it On & Off a few times while running.
May just have some junk in it preventing Choke Needle from seating closed.
You may want to take it off,,verify that the needle moves in/out with the Choke switch.
And spray some Carb Cleaner in the Hole.
Make sure the Screw-In Seat for the Choke Valve is Snug also.
A REALLY Dirty Air Filter will richen it quite a bit,,,but not as bad as yours sound.
It's worth checking for anything that may have gotten inhaled,,like paper,plastic,trash etc,,,,,which would Block the Filter's Intake LOTS more than just a plain 'ol nasty filter.
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Those things have a Fuel Pump that operates off engine vacuum.
If you removed any hoses from engine area ,,,
It's Possible the Fuel and Vacuum Hoses have become reversed.
On a convential Motorcycle with Gravity Feed Tanks,,and vacuum operated fuel valves,,,"Crossing" the hoses Just instanly Pours gas straight into engine and Fills it up.
On Scooters,,it acts a lot different.
They run Ok for a minute until Carb runs out of Fuel.
The Fuel Level in the Carb BLOCKS the "crossed-hose" Vacuum from getting to the Pump.
So ,,Pump doesnt pump>no vacuum to operate it.
But once carb runs Dry,,,THEN Vacuum CAN reach the Pump,,,via a really weird,restricted path thru the Dry Fuel Bowl.
So Vacuum Pump gets a faint,weak Vacuum pulse.
But enough to make it pump a small amount of fuel from Fuel Line Directly into Engine/Intake Vacuum Port.
So Vacuum Fuel >PUMP< Motors DONT immediately Fill Up with Fuel,,,, like Vac-Operated Fuel >VALVE< motors.
The Vac-Op'd VALVE set-ups act the same as pouring gas straight into Spark Plug Hole until cylinder is filled.
Motor obviously wont run at all.
The PUMPED set-ups,like most scooters,,,get a relatively Large SQUIRT of raw gas into intake.
Same as using a squirt can and squirting it into Carb Throat.
Way,Way too much gas.
But still very Possible for them to Run,,,however Rich and Badly and Briefly.
That's a lot of spam about Crossed Hoses,,,,It Happens often enough(easy mistake to make) and "everybody " knows the results of that on Motorcycles.
Scooters act Differently when it happens,,,and produce some Unique & Unusual Symptoms .
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Some other possibilities,,,,these are RARE,but possible.
* Ignition System going bad,,,which rarely produces the symptoms of Yours
* Flywheel Key "Half Sheared" throwing the Ignition Timing far off Enough to run really Bad,,,but still be able to start & run
* Exhaust Restrictions:
A 4 Stroke Engine cannot hardly become carboned-up enough to cause such severe running problems.
2Strokes certainly can,and DO,,,but not 4 Strokes.
What ANY exhaust system CAN do is to have Internal,Mechanical Damage.
Stuff Breaks INSIDE the pipe/muffler.
Baffle Plates,Tubes,etc come loose and float around till they stop-up/block/restrict the Outlet path.
It's something we often HEAR about as if it's a common thing,
It's NOT common at all.
But it DOES happen and produces a VARIETY of odd symptoms which dont seem to correlate to standard troubleshooting.
It can "act like Anything" because the failures can occur in a variety of ways.
And,,it can be Intermittent---the probs seem to come & go,,or get "better then worse".
Don't go off on a wild-goose-chase witch hunt after Exhaust Probs,,,but if all else fails it's worth ;
a)making sure head pipe/straight pipe is Clear,,,
b)try running itt with "muffler" removed .
Thats all the LAST thing to try before calling an Exorcist.
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* Carb-..Most Likely root cause item
-Float Bowl Flooding from bad fuel valve
-Choke system malfunction
-Fuel Line crossed with Vac Line
*Air Filter & AirBox inlet,,,,smothered with foreign object/material
(Not likely,but easily Possible)
*Ignition system fault--Not Likely,but somewhat possible
---failing CDI Box
--Sheared Flywheel Key
*Exhaust restriction,,,Least likely problem.
RARE,but possible
Good Luck with it RUNNING HOT , NEED TO ADJUST THE CARB You are running way too rich, check the choke if your engine isnt getting enough air it will act like its bogging down..check to see if the float is sticking also..as this could cause it to flood the chamber with fuel and cause it to die down.....usually when any black smoke or soot is seen it means the air to fuel mixture is wrong....bob If you look at the carb from the side that the choke is on
There is a top screw that adjusts the throttle idle
And a screw right below that - which is your mix screw - you need to loosen that one 1/2 turn at a time - till you get it right.
Mine is set for 89 Octane right new and golden specre 2 stroke oil. - turn it all the way tight and back it out 1-1/4 turns to run like me.
I run a Champion plug in it - and I have ran about 25 tanks through it like it sits.
I am 165 LBS and had it to 35MPH.
I have another that I race and that goes 60 MPH you only need regular gas, and it sounds like your choke is stuck on, or your float has crud in it and is letting in too much fuel.
Heres why you dont need anything other than regular.
http://www.bajajusa.com/High%20Octane.ht...
and maintenance on Chinese scooters.
http://www.motorcycles.pro/ScooterScams/...
oh, does it exceed 30MPH? you may need an endorsement anyway, What state are you in?? |
