Fuel...

GoldenMotor.com

Kurtis100

New Member
Feb 2, 2015
10
0
0
Canada
My 66cc engine seems like it's not getting enough fuel in the engine. I start it up and I can ride it and it goes 100% then it kinda starts bogging down. I unplug the fuel line and pour a bit of gas out and it comes out in little drops then flows out normally 2 seconds later. Then the bike rides perfectly again. The same thing 2 minutes later. Is this something to do with not getting enough air in the tank that it slows the gas flow?
 

Agreen

Member
Feb 10, 2013
792
11
18
Southeastern GA
It doesnt take much to run these little guys. My fuel valve flows very little as well. I tried draining the tank through it once so i could paint and only got a very slow drip rate.

I would suspect something may be hanging up in the carb? Maybe the float is set too high or low, or the needle is on the wrong notch?
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
These tanks are notorious for having all kinds of junk inside them from the factories in China like metal shavings, paint chips, small pieces of news paper and who knows what all else. If you didn't clean out the tank before installing the petcock and that little screen filter then this is probably why it just barely trickles out.
I've had a customer's bike come to me with a similar problem where it would cut out and then work and then cut out again and it had the same problem, the fuel would just barely trickle out of the tank one time than it would come out as a steady stream.

I took of the petcock and poured the fuel mix into a waste oil container then washed out the inside of the tank, the little screen filter on the petcock was covered with junk from the tank so I took it off and blew it out with compressed air, then made sure nothing was obstructing the petcock, put it all back together and refilled the tank with fresh mix, opened the petcock and let it drain back into the gas can and problem solved. This one also got a new fuel filter just to be safe, but it was flowing way better just by cleaning all the junk out of the tank.

If you were running without a fuel filter then definitely check the carb too, things can block off the needle and seat valve and main jet which will cause the engine to cut out intermittantly and randomly... This problem can also be caused by the fuel valve on the NT Speed carb, I've had one that would cut out like this and found little rubber particles blocking off the needle and seat valve and found the culprit to be that rubber disc that's in the fuel shutoff valve that's built onto the carb so I just gutted it out since there's really no need to have 2 fuel valves anyway.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
first thing to do is check flow properly by taking out the drain screw on the carb bowl and watching fuel flow for a while (I use a cut off piece of funnel to flow it into a jar)

you may find that it flows well, then stops which usually means that the air vent in the gas cap isn't working (take gas cap off and see if it flows)

gas cap can be drilled to make a new vent hole

if not the cap, then check both fuel filters for clogs
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Very true... if the gas cap vent isn't venting it can stop the fuel flow just as quickly as a clogged filter... simple fix as mentioned above....