New engine not starting

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Mopig

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Dec 4, 2012
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Here's what I'm working with:

66/80cc Flying Horse Silver Angle Fire Bicycle Engine Kit - 2 Stroke

New CDI installed and wired correctly. Spark plug wire assembly replaced with new automotive type.

New NGK replacement spark plug.

I'm getting good spark.

I've tried getting it started shooting a little starter fluid into the engine via the air intake. No dice. Not even a cough.

Fuel and tank are clean with fuel mixed at about 20:1

This kit came with the basic NT carburetor meaning no adjustments other than the idle screw.

First question. The small spring loaded push button on the carburetor. Is that supposed to be a primer like on other small engines like mowers and weed eaters where pushed it shoots a small stream of fuel? If so I get nothing squirting when it's pushed and I know the carburetor bowl has fuel as I've taken this carb apart already to inspect it and it was full of fuel.

Seeing how I have good consistent spark it's got to be a fuel issue meaning the carb.
 
Last edited:
2door

2door

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Sep 15, 2008
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If you took the carburetor apart it should have been easy to see that the 'primer' or 'tickler' does nothing more than push down on the float thereby allowing more fuel, an excess amount, to flow into the carb giving you a fuel enrichment for cold starts. It is not a "pump". You won't see any squirting.

How are you confirming that you have ignition?
How are you confirming that fuel is flowing from the tank to the carburetor?
Have you tried starting the engine with the choke closed, or partially open?
Have you confirmed that the main jet is in place and not laying in the bottom of the bowl? They sometimes come loose and fall out.
Is the throttle functioning properly?

Tom
 
crassius

crassius

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Sep 30, 2012
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Some new engines need the choke for the first start or two, but with the fluid you should have gotten something.

I've seen spark plugs that spark nicely out of the engine, but not under compression in the engine, a fresh one may help.

I've seen CDI units that make a nice spark, but at the wrong time due to a bad trigger inside them, if you have one known to be good, you might try that.

Then there're all the usual things like no compression, slipping clutch, and rotor not on the keyway right.
 
M

Mopig

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Dec 4, 2012
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-Pulled plug and tested for spark while turn engine over. Good spark. New plug.
-Pulled fuel hose from carb and fuel flows as it should to the carb. Fuel bowl has been full every time I've taken the carb back apart.
-I've tried starting it with the choke closed, open, in between, wet plug, dry plug, a shot of starter fluid, I've tried all the normal options I know of.
-Throttle functions properly. No sticking, it slides up and down smoothly.

-I guess I can pull it apart again and check the main jet again.

-Pushing down the "primer" I see no added fuel flowing into the carb, so that may be where the problem lies. Something plugged.

I'll pull it apart again and verify all holes are clean and unblocked.
 
2door

2door

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Sep 15, 2008
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Did you by any chance remove the magneto rotor (magnet) from the crankshaft? It can be installed backwards which throws off the ignition timing. You'll get spark but not at the right time.

If there is fuel in the bowl then the float needle valve is open but it never hurts to assure that it's clean. We alwasy suggest that a new fuel tank be clean well before installation and that an in-line fuel filter be installed between the tank and carburetor.

If you get no evidence of firing using a starting fluid I would be suspicious of the ignition.
Even with no fuel and if you inject starting fluid into the inlet of the carb, that thing will fire. Not long, but it will pop. If it doesn't there is something going on in the ignition circuit.
Is the kill switch (button) wired into the circuit? If so disconnect it temporarily for testing. They are notorious for malfunctions.
How is the engine wired?
What is the plug gap? .024 to .028 is a good starting point.
How old is the gasoline mix? 20:1 is a little oil rich but shouldn't keep the engine from running. Mixed gas/oil has a short 'shelf life'. We don't recommend keeping it setting for long periods. a month is pushing it. Old gas will run but not well.

Tom
 
M

Mopig

New Member
Dec 4, 2012
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I did remove the magneto and remove the varnish from the backside to insure good contact. Didn't remove the magnet from the shaft. I re-installed what I did remove in the same way it came off. And looks correct when comparing to other pictures.

I haven't bothered plugging in the kill switch so that's a non player.

I did flush the tank, installed a filter, and used real fuel hose instead of that clear plastic tube that leaked right off the bat. The gas mixture is only about a week old, so it should be good.

I re-checked the spark plug gap and it's set to .025. (NGK BP6HS). I checked for spark again and it looks pretty bright when I lift the tire and kick the engine over with the peddles.

I just finished pulling the gas tank out, dumping it (looked clean), filled with fresh gas/oil mixed at more like 25:1 now, and pulled the carb apart down to the last piece. Clean as a whistle still.

I've gone through Fisherman's no start guide, but I'll look it over again in case I missed something which is entirely possible.

Think I'll call it a day on this project otherwise and hit it again later. I've got an Aprilia SR50 I still need to get back together once I've got the fuel pump repaired.

Thanks for the tips.
 
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2door

2door

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Sep 15, 2008
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Littleton, Colorado
It sounds as if you've covered a lot of the basics. How does the compression feel? Is there a substancial resistance when you turn the crankshaft against a compression stroke? Or does it turn easily? I have to assume from your comments that you're no stranger to internal combustion engines so you'd know if things 'feel' right as far as compression goes.
I also assume that you'd know when you're pedaling, clutch engaged, if the engine is turning. We have had cases where the clutch was slipping with predictable results.
Keep us informed as to what you find. Your discovery might help others.

Tom
 
the chief

the chief

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Dec 9, 2012
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i would also guess a problem with the spark, with starter fluid it should at least cough, one possiblity though, clutch cable. undo it and roll the bike, note the amount of resistance that it gives, is this the same resistance that you get when the clutch is hooked up? if it is not give it a little more slack, could be that your cable is too tight and your clutch is slipping.
 
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