Whats wrong with my 49cc 2 stroke engine? PLEASE HELP!

[Stan4d]

I checked on a web site that sells the RacerX scooter, which is what I have, and they recommend 32:1 oil ratio.
Ironically that is what I run in all my 2-strokes anyways.

I deleted my earlier post because I noticed he said he could find nothing on his motor, and you had already said you were experienced with them. Thank you for that bit of info, it is a question that was running around in my head.
My weedeater wont run on that mix. Thats why I was wondering.

 

[rob0101]

so this morning i have spent cleaning yet again the carb, but i also cleaned out the fuel tank, fuel filter, checked the fuel lines, checked the seals from the carb to the engine. i put it all back together and...STILL THE SAME :O

so...

can anyone tell me how many turns in roughly the high speed fuel mixture screw should be in, ive got it at 10 full turns in at the moment

also...

just a thought, what should the gap be on the spark pug for this engine?

thanks for your help!

 

[aero07]

so this morning i have spent cleaning yet again the carb, but i also cleaned out the fuel tank, fuel filter, checked the fuel lines, checked the seals from the carb to the engine. i put it all back together and...STILL THE SAME :O

so...

can anyone tell me how many turns in roughly the high speed fuel mixture screw should be in, ive got it at 10 full turns in at the moment

also...

just a thought, what should the gap be on the spark pug for this engine?

thanks for your help!

I had to tinker with my carb as well. I turned the high speed fuel
mixture screw all the way in, then out 2 1/4 turns. Also turned idle screw in
to get the right idle.
This might not work for you but it worked for me.

 

[GearNut]

!!!WARNING!!! The following procedure can be very dangerous if you do not take proper precautions and plan out your work!!! Fire directly on the carburetor is involved!!!

There is a low speed adjuster screw as well.
It is recessed down in the center of the brass fitting that the throttle cam attaches to.
If you look at it you will see the hole that the screw threads down in to.
On my carburetor it was sealed up with superglue from the factory to prevent folks from messing with it. I had to mess with it to get it to run correctly.
I used a small butane pencil torch to burn the superglue out of the brass fitting. You have to be careful that you do not overheat the brass or else the plastic throttle cam could melt in the center. After 2 seconds of heat, the superglue reached it's burning point and burned up with a quick "poof" and was completely gone. It burned up surprisingly fast. The brass was barely warm to the touch.
If you do try this, be very careful around the gas fumes! Do it out doors and have a fire extinguisher close at hand.

The screw is very sensitive to adjustment. 1/8 of a turn made a big difference. I recommend adjusting it with small fractions of a turn. I messed with it with the engine both hot and cold to fine tune it for easy starting, good idle and smooth acceleration.
Keep notes on the adjustments you make to all 3 screws. It makes the adjustments much easier to keep track of so you get a better understanding of what works and what doesn't.

 

[rob0101]

hey GearNut, no sure im really confident putting a flame to my carb lol, and i cant really see a screw for low speed settings on my carb, just looks like solid metal in the hole? here is a picture...

no i remember, when i first got this engine i was told to put in 40:1 petrol/oil mix, i thought this was abit lean so have never done...and its never run right, so could this be causing my problem? will this do damage? unless told otherwise ill give it a shot tomorrow, im running out of ideas fast!

thanks!

 

[GearNut]

I took a few of pics of my carb. In 2 of them you can see the screw I am talking about.
If your carb does not have this low speed mixture screw, then I can only surmise that it is a production change.

40:1 will give a slightly richer air/ fuel ratio. I do not see it hurting anything to just try it out.

As said previously, my engine wants 32:1, the manufacturer told it so. Some 2-stroke yard tools want 50:1.
40:1 is a good middleground.

 

[rob0101]

thanks GearNut

did abit of digging with a pin in the screw and it does have a screw head glued in there, but i only have lighters and dont want to catch fire so i cant really get to it lol

tried it with 40:1 fuel...no change i am COMPLEATLY out of ideas

gonna have a friend have a look at it and if i still have no luck just going to buy a new carb, they are £14 including Postage here so its not too bad, i have been defeated and just want to get it running now!

thanks.

 

[rob0101]

IT WORKS!

And for future reference to anyone else having the same problem with this kind of engine as i did, i will tell you what i did...

The problem was the engine was not getting enough fuel, i.e the needle that moves up and down to control fuel flow was set too long and thus not letting enough fuel in. as this needle was glued in really well adjusting it with a screwdriver was not an option. i toyed with cutting the needle abit shorter with a hack saw or wire cutters but this was an irreversible modification which i was not confident with. so instead i went with a specially modified washer, i found a washer that was only a few millimeters bigger than the screw head of the screw the needle sits in, and cut it into a 'C' shape so that it fitted in the recess of wear the screw head would normally sit, this way it only raised the needle about 2mm. and thats it! the engine runs exactly how its supposed to with the choke fully open and revving without dying. There is a very tiny bit of oil spitting from the exhaust but ive been told this is not a bad thing.

Below is a picture of my home made washer in action...

Thanks for all the help i have received on here from various people!

 

[GearNut]

Congratulations on your repair!
As the old saying goes, "there is more than one way to skin a cat".
That is a rather ingenious way to adjust the needle position!

 

[adb140275]

glad you got it fixed