New Build Won't Start

J

jboom

New Member
Hi guys. I've been fighting with this POS Flying Horse 66cc since the day I got it (just regular carb that comes with standard model). I got it all put together (delicately or you'll break it) and took it on it's maiden voyage and boom she fires up dance1 but just for a minute and WOT. I still considered this a success. So I made a few adjustments and went back out and managed to get her to start again and let her sit there and idle (roughly) for several minutes before killing it. I went and ran some errands and came back a few hours later and tried it again and nothing...:-|| I've been troubleshooting everything I can think of for the last few days. The sparkplug was black so I bought the NGK 6 (can't remember exactly but it's the one recommended) and it won't fit in the cap. I even unscrewed the fitting inside the cap and it still doesn't fit. But we I can worry about that latter. Put the old plug back in, turned out the lights and spun the wheel and I see sparks. Yeah baby!! Siliconed the intake, changed the fuel to 50:1 (sythentic, just to try to start it for now) and sprayed starting fluid in the air filter. Then I pedaled like a mad man. Nothing. I tried full, half, and no choke. It did try to start for just a couple of seconds but that was it (enough to burn off the starting fluid maybe?). Just enough to tease me to stay on it. I think it's in the carb but I'm not a carb guy at all. Please help.
 
You need three things. Fuel, air and ignition.

Have you confirmed that fuel is flowing from the tank to the carburetor? Clogged fuel flow is common with a new fuel tank. They need to be cleaned before installing.

Checked to make sure the choke is opening? Sometimes the choke plate is loose and will close on its own or doesn't open when you move the lever.

You've confirmed ignition, at least with the plug removed. A defective kill switch can also cause you grief. Try disconnecting it and check your wiring connections. The kit supplied push-togther connectors are not very good. We suggest soldering the wire splices and protecting with heat shrink tubing. If you have a magneto with a white wire make sure that it isn't touching any metal. The white wire needs to be capped/insulated against contact with anything.

As for the spark plug, that plastic kit supplied spark plug boot needs to go in the trash. They are the weakest link in the kits. Replace it with a good automotive quality plug boot then your NGK plug will work. The kit boot requires that the top cap be removed from the plug exposing threads. That is where most of your ignition problems start.

You need a good electrical connection at the plug. The kit boot and the way it attaches to the plug won't assure that. The wire connection is also questionable. The kit boot is probably responsible for the biggest majority of "won't run" problems for new builders.

Tom
 
Thanks for the reply 2door and crassius. I'm getting flow from the tank I know because that's how I drained the 16:1 fuel out to replace with 50:1, pulled the line off the carb. I capped the white wire yesterday. I also put some tape around the other wire connections the other day. I learned they fall out the hard way also when I first got her to fire up and was WOT to an intersection. Got it to stop Fred Flintstone style. Had to go Flintstone because when I put the gas tank on I crimped my brake cables lol.

That crappy boot broke the first time I put it on the plug. I've got it taped together with electrical tape. Think I'll go to Autozone today and get a new boot. Is there any certain one I should buy?
 
I'm a bit anal when it comes to spark plug boots and connections. I use the crimp on metal connector that pokes through the insulation with a sharp prong but I also solder the wire to the connector before installing it in the rubber boot. Soldering requires drilling a 1/16" hole in the connector but that's easy.

That might be overkill but I'm assued of a troublefree plug connection.

Tom
 

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Great pic. Thanks for the help. I'm also going to check the choke. Do you think there could be any other problems in the carb? I pressed the primer button on the carb yesterday and I could see fuel moving through the fuel line. I'm just not sure if it's getting to the cylinder. The plug doesn't look wet at all like people talk about. I'm determined to get this motor running or I'll at least learn every little detail about it in the process.
 
I just re-read your original post. I'm a little concerned when you say the engine started then went to WOT.

Have you confirmed that your throttle is working properly. If the throttle is stuck open that could certainly impact getting it started. Also it's a dangerous condition. Remove the air filter and look into the carb throat while twisting the throttle open and closed. You should see the slide move up and down.

If the throttle isn't working the barrel or slide might be installed backwards which will prevent it from working. The long slot on the side of the barrel goes to the right as you're looking down on the carb. The short slot should align with the idle speed screw on the left side.

Overtightening the cap where the throttle cable enters the carb can also cause the barrel to stick/bind. Finger tighten that cap only. Use no tools. Overtightening can distort the carb body.

The "primer" or 'tickler' button is just a simple device that pushes down on the float, sinking it and opening the float needle valve to allow fuel to flow into the carburetor bowl. It is to provide a way to give you a slightly rich mixture that can sometimes help starting under certain conditions. It isn't a pump but if held down for more than a few seconds will flood the engine and causing fuel to leak out the intake.

Keep us informed of what you're finding.

Tom
 
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I bet I flooded the engine then. I pressed it down more than once. Learning is fun lol. I'm trying to upload some pictures here. I found what looks to be a hole in my engine by the intake. Can't tell if it's got air coming out of it or not.
 
Starting fluid is a no-no for 2 stroke engines. Use pb blaster.

Try this (since you at least have spark):
If you have a stand, prop the bike up and use the pedals to kick start the engine while a helper sprays pb blaster in the carb.

Also, does the engine feel like it has good compression? When I built my first one, I just bolted it on and was flying around at WOT immediately. Then I found out how bad that was. The engine needs to be broken in before going wide open like that. I tore it down after a couple of tanks and had huge score marks on the cylinder. I was also informed that i should have torn the engine down before installing it because they are generally full of metal shavings from the factory. I did that on my second build, and I cleaned out a lot of metal debris.
 
spark plug will be shiny wet if fuel is flowing properly into cylinder

a hole in the intake pipe (near the weld) is usually a hole & a problem

a hole in the cylinder casting near the channels where the head studs run is usually just bad casting & not a problem
 
I have holes in both areas. One where the intake mounts to the cylinder, it's smaller. Then I have one where the head studs run. It doesn't really look like a hole though. Don't think I can push anything through it. The hole where the intake is I could fit a pencil lead through. I sent the pics to bikeberry. I'm going to put some silicone on it tonight.
 
take it off, hold it in hand with opening against palm, blow in other end - you'll know then if the hole goes thru
 
It was definitely a hole. I bought some high heat JB weld (not really JB but it's similar) and put it over the hole last night. I've gotta let it dry for 4 hours so I'll try it again this evening. I've read on some threads where people had to turn there motor upside down to drain it. I wonder if I need to do that also. Seems like I have some of the same symptoms they had. Can I drain the gas, take out the plug and then just turn her over? Thanks for all the help guys!!
 
usually just pedaling it a bit with plug out will clear it, but it usually only fills up if petcock is left turned on while bike is leaning on kickstand
 
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