Engine wants to go, but something is killing it!

S

saabengineer

New Member
Hi all, I am in the process of breaking in my 2010 Grubee Gt-5 66/80cc engine. The first time I started it I took it pretty easy varying the throttle range and not going over 15mph. I did the same thing the second time I started the engine and ran a little better as expected.

Now I am having trouble with the engine running. When I release the clutch, the engine wants to run but when I give it gas it dies. And if I don't give it gas it dies. If I assist the engine by pedaling it will stay on. While i'm pedaling I try to give it a little gas and the engine bogs down and dies. Tonight I got it running for about 7 seconds while keeping the rpms above idle. I can get the engine to run only if I pedal assist. What is going on? The engine wants to run! :-||

I used the recommended 1:16 gas mix for break in. I have the CNS carb too. I have heard there is a sweet spot for these carbs. "From the posts Ive read the sweet spot on the mixture screw is 1 to 1.5 turns out from all the way in." Should this be done even on break in? I have not messed with any of the settings at all.
 
I guess first check the plug for color and/or fouling (never take the plug out of a hot engine or the threads may come out with it),,,,16/1 is pretty heavy mix
http://motorbicycling.com/f13/aftermarket-spark-plugs-14664.html
from BarelyAwake from another thread
Perhaps, but the fuel/air mix should only be adjusted for proper burn, using the spark plug electrode's color as a guide - black & oily & it's too rich, gray/white & it's too lean (air/fuel screw out for leaner, in for richer). However - I gotta say 16:1 fuel/oil is too heavy a mix even for break in so that would effect it too. I'd recommend a quality 2-stroke oil @ 32:1.

you can type in symptems in the google bar at the top of the page and then scroll down for threads w/answers
 
16:1 is an archaic leftover from when these motors were first made in russia. they were using regular motor oil back then. a good start is 24:1 with your basic cheap oil.

besides that, it did run, so i don't think mixture is the problem.

first thing i'd check is the carb. make sure it's tight, the manifold's tight, and there's no air leaks. you say you can start it by messing with the throttle, so it sounds to me like it's trying to get the right mixture to run. and if it's sucking in too much air where it's not supposed to, then throttling it could compensate for that.
 
Is your cns carb tight on the intake ? Have you done the spray test to see if you have air leaks between the carb and intake ?
 
Thank you for all of your replies. I checked the spark plug yesterday and it was black and oily. But it did run befor. I cleaned the plug and did get the engine to run for 7 secs. I will check the CNS carb to make sure its tight. If I am still having trouble with it starting I will lean out the mix. Unfortunately I can only do this in my garage because it is raining here in Washington!

I am using the cheap spark plugs for break in right now since I have two. The spark plug seems to be a little longer than the plugs that came with the Grubee engine. I bought the NGK BP6HS plug from sick bike parts. I am worried that it might be too long and hit the piston.
 
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I checked the CNS carb and it is tight. I also tightened all bolts down to make sure their are no air leaks. It wants to start still but just wont give me any power when I throttle. I can pedal assist to keep the motor running but as soon as I give it a little throttle it bogs down and dies. What is going on? I wanted to use this to get around on school.
 
At 16:1 your plug is bound to be black and oily no matter what your air/fuel ratio is but these engines will run on that. My first GT5 had over 100 miles on it before I switched to 40:1. If you can get it running try fiddling with the choke. If it runs better with a little bit of choke you either have an air leak or a restricted fuel line. Make sure none of your vent hoses coming off the carb are kinked
 
I'd check ya head bolts too they can sometimes end up loose very quickly.
Check ya electrical connections are done really well.
Make sure ya spark plug lead cap is secured properly if ur running the standard plug lead that brass lookin screw bit needs to screw off the spark plug you'll hear it go on properly.
You wanna b sure there's no leaks go around with a Torch and look for gas or oil anywhere then let us know where that is.
More than likely though it'll be ur carb but rule out all the simple stuff 1st so ya don't end up chasing ur tail.
 
16:1 won't be ur problem I ran that when I was a newbie for ages on dud cheap ass 2stroke oil too. It wont help ya but shouldn't really hinder u either
 
gas cap not vented i
saabengineer said:
Hi all, I am in the process of breaking in my 2010 Grubee Gt-5 66/80cc engine. The first time I started it I took it pretty easy varying the throttle range and not going over 15mph. I did the same thing the second time I started the engine and ran a little better as expected.

Now I am having trouble with the engine running. When I release the clutch, the engine wants to run but when I give it gas it dies. And if I don't give it gas it dies. If I assist the engine by pedaling it will stay on. While i'm pedaling I try to give it a little gas and the engine bogs down and dies. Tonight I got it running for about 7 seconds while keeping the rpms above idle. I can get the engine to run only if I pedal assist. What is going on? The engine wants to run! :-||

I used the recommended 1:16 gas mix for break in. I have the CNS carb too. I have heard there is a sweet spot for these carbs. "From the posts Ive read the sweet spot on the mixture
Click to expand...
 
check the plug,check the carb. for loose or loose screws ,I've seen many things on here that it could be ,,have you tryed the search bar at the top of the page yet,lots of answers are there already
 
Well, I'll tell you some of my problems
and you can compare:

My thread

Mine would not start at all.
Checked for spark;
Checked for leaks;
Checked for fuel in the cylinder;
Inspected inside the carb
for garbage;

It started after I put fresh fuel
in it and I used the higher octane.
Now this may not have been the
problem though, I'm suspecting
that it might have been flooded
and the amount of time I left it
still, cleared the flood.

It runs okay now, however there is
a warm up period before it runs
smoothly. During this period is
similar to what you are describing
and needs a bit of choke to get
it going.

Also check the plug for correct
gap. Mine has three electrodes
and one of them the gap was
too tight.

Check the magneto for loose screws
and any bare wires from the magneto.
Vibrations with bare wires could
cause it to short.

It still sounds more like carb though.
 
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